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The Elements
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The Periodic Table of the Elements

What is the Periodic Table of Elements?

Although scientists know of many elements, the properties of many of them are similar. Thus if they are grouped on the basis of their properties, it becomes easy to study and compare their properties. The periodic table of elements is a way of organising all the known elements. In the early days, elements were classified into only two groups: metals and non-metals. But some elements showed the properties of both metals and non-metals. They were called as metalloids.

History of the Periodic Table

Early History

People have known about basic chemical elements such as gold, silver, and copper from antiquity, as these can all be discovered in nature in native form and are relatively simple to mine with primitive tools. Aristotle, a philosopher, theorised that everything is made up of a mixture of one or more of four elements. They were earth, water, air, and fire. This was more like the four states of matter (in the same order): solid, liquid, gas, and plasma, though he also theorised that they change into new substances to form what we see.

Hennig Brand was the first person to discover a new element. Brand was a bankrupt German merchant who was trying to discover the Philosopher's Stone — a mythical object that was supposed to turn inexpensive base metals into gold. He experimented with distilling human urine until in 1669 he finally obtained a glowing white substance which he named phosphorus. He kept his discovery secret, until 1680 when Robert Boyle rediscovered it and it became public.

By 1809, a total of 47 elements had been discovered. As the number of known elements grew, scientists began to recognize patterns in the way chemicals reacted and began to devise ways to classify the elements.

Antoine-Laurent de Lavoisier

Antoine Lavoisier's Traité Élémentaire de Chimie (Elementary Treatise of Chemistry, 1789, translated into English by Robert Kerr) is considered to be the first modern chemical textbook. It contained a list of elements, or substances that could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulfur. It also forms the basis for the modern list of elements. His list, however, also included light and caloric, which he believed to be material substances. While many leading chemists of the time refused to believe Lavoisier's new revelations, the Elementary Treatise was written well enough to convince the younger generation.

This model only classified elements into metals and non-metals and thus was not accepted.

Alexandre-Emile Béguyer de Chancourtois

Alexandre-Emile Béguyer de Chancourtois, a French geologist, was the first person to notice the periodicity, the periodic or repetitive nature, of the elements — similar elements seem to occur at regular intervals when they are ordered by their atomic weights. He devised an early form of periodic table, which he called the telluric helix. With the elements arranged in a spiral on a cylinder by order of increasing atomic weight, de Chancourtois saw that elements with similar properties lined up vertically. His chart included some ions and compounds in addition to elements. His paper was published in 1862, but used geological rather than chemical terms and did not include a diagram; as a result, it received little attention until the work of Dmitri Mendeleev.

John Newlands

John Newlands was an English chemist who in 1863 classified the 56 elements that had been discovered at the time into 11 groups which were based on similar physical properties. He noted that many pairs of similar elements existed which differed by some multiple of eight in atomic weight.

The first periodic table

Dmitri Mendeleev

Dmitri Mendeleev, also spelt Dmitry Mendeleyev, middle name (patronymic) Ivanovich, a Siberian-born Russian chemist, was the first scientist to make a periodic table much like the one we use today. Mendeleev arranged the elements in a table ordered by atomic mass. It is sometimes said that he played "chemical solitaire" on long train rides using cards with various facts of known elements. On March 6, 1869, a formal presentation was made to the Russian Chemical Society, entitled The Dependence Between the Properties of the Atomic Weights of the Elements. His table was published in an obscure Russian journal but quickly republished in a German journal, Zeitschrift für Chemie, in 1869. It stated

1. The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties.
2. Elements which are similar as regards to their chemical properties have atomic weights which are either of nearly the same value (e.g., Pt, Ir, Os) or which increase regularly (e.g., K, Rb, Cs).
3. The arrangement of the elements, or of groups of elements in the order of their atomic weights, corresponds to their so-called valencies, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, Ba, C, N, O, and Sn (probably an error for Li, Be, B, C, N, O and F, since the symbols for the elements weren't completely standardized yet at that time).
4. The elements which are the most widely diffused have small atomic weights.
5. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body.
6. We must expect the discovery of many yet unknown elements–for example, elements analogous to aluminium and silicon–whose atomic weight would be between 65 and 75.
7. The atomic weight of an element may sometimes be amended by a knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between 123 and 126, and cannot be 128.
8. Certain characteristic properties of elements can be foretold from their atomic weights.

Advantages

• Mendeleev predicted the discovery of other elements and left space for these new elements, namely eka-silicon (germanium), eka-aluminium (gallium), and eka-boron (scandium). Thus, there was no disturbance in the periodic table.
• He predicted (often accurately as it turned out) properties of some of these then missing elements as well as properties of some of their compounds.
• He pointed out that some of the then current atomic weights were incorrect.
• He provided for variance from atomic weight order

Drawbacks

• There was no place for the isotopes of the various elements.
• His table did not include any of the noble gases, which hadn't been discovered. But these were added by Sir William Ramsay as Group 0, without any disturbance to the basic concept of the periodic table.

Unknown to Mendeleev, Lothar Meyer was also working on a periodic table. In his work published in 1864, Meyer presented only 28 elements, classified not by atomic weight but by valence alone. Also, Meyer never came to the idea of predicting new elements and correcting atomic weights. Only a few months after Mendeleev published his periodic table of all known elements (and predicted several new elements to complete the table, plus some corrected atomic weights), Meyer published a virtually identical table. Some people consider Meyer and Mendeleev the co-creators of the periodic table, although most agree that Mendeleev's accurate prediction of the qualities of the undiscovered elements lands him the larger share of credit. In any case, at the time Mendeleev's predictions greatly impressed his contemporaries and were eventually found to be correct. An English chemist, William Odling, also drew up a table that is remarkably similar to that of Mendeleev in 1864.

Henry Moseley

In 1914, Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number and therefore resequenced the table by electronic charge rather than atomic weight. Before this discovery, atomic numbers were just sequential numbers based on an element's atomic weight. Moseley's discovery showed that atomic numbers had an experimentally measurable basis.

Moseley's research also showed that there were gaps in his table at atomic numbers 43 and 61 which are now known to be radioactive and not naturally occurring. Following in the footsteps of Dmitri Mendeleyev, Henry Moseley also predicted new elements.

Glenn T. Seaborg

During his Manhattan Project research in 1944, Glenn T. Seaborg experienced unexpected difficulty isolating Americium (95) and Curium (96). He began wondering if these elements more properly belonged to a different series which would explain why the expected chemical properties of the new elements were different. In 1945, he went against the advice of colleagues and proposed a significant change to Mendelev's table: the actinide series.

Seaborg's actinide concept of heavy element electronic structure, predicting that the actinides form a transition series analogous to the rare earth series of lanthanide elements, is now well accepted in the scientific community and included in all standard configurations of the periodic table. The actinide series are the second row of the f-block (5f series) and comprise the elements from Actinium to Lawrencium. Seaborg's subsequent elaborations of the actinide concept theorized a series of superheavy elements in a transactinide series comprising elements 104 through 121 and a superactinide series inclusive of elements 122 through 153.

Introduction

Graphite. Pencil lead is made of graphite. Graphite is made up of the element carbon.

To know what "Elements" are, you need to know about chemistry. So, what is chemistry? Chemistry is the study of matter and the changes that take place within that matter. Unfortunately, this does not tell you very much about chemistry, and it is also a very long way from telling you EVERYTHING about chemistry.

Everything on Earth, everything in our solar system, everything in our galaxy, and everything in the universe is made up of matter. Matter is the name that scientists have given to everything you can touch, or see, or feel, or smell. Matter takes up space, and matter has weight. To be really correct, we should say that matter has volume and mass. In other words matter has substance, and "Elements" (about 118 of them) are what gives matter its substance, even what makes it exist at all.

Most of the matter around you will have more than one element in it. But there are bits of matter that you have certainly seen and touched that are made up of just one element. If you have ever held a diamond, for example, it has been formed from just one element, the element Carbon. Surprisingly, the graphite in a pencil that you use for drawing or writing is also Carbon, just arranged differently.

Some other examples of matter you may have seen which have just one element are: an aluminium drink can; 24 carat gold jewelry; the helium gas in a balloon that floats upwards; cast iron garden railings; lead sheeting used by builders on the roofs of houses; a powder called "Flowers of Sulphur" that you can buy in a pharmacy.

In actual fact these are not perfectly true examples of elements, because an element, like gold or aluminium, will always have tiny amounts of other elements present as impurities.

Not many elements occur "naturally;" that is to say as pieces of nearly pure substance that you can pick from the ground. The elements Gold and Sulphur do occur naturally, as does Carbon when it is a diamond.

To purify them, most elements have to be pried apart from one another, because in most matter they are fixed together by strong "chemical bonds." Sometimes this can be done quite easily by using heat or electricity.

Ancient people knew how to make the element Iron. They did it by heating iron ore dug from the ground with charcoal they got from burning wood. The matter containing the iron was originally a "compound" of two elements, iron and oxygen; by heating with charcoal the oxygen was removed as a gas called carbon dioxide, leaving iron behind.

The elements Sodium and Chlorine can be separated from common salt by passing an electric current into salt that is melted at a very high temperature. The salt we started with is said to be a "compound" of sodium and chlorine. It is given the scientific name of sodium chloride.

One interesting source of elements is the air around us. It contains a mixture of elements that are all gases, such as Oxygen which you will have heard of already, as well as many gases which are not elements but are compounds — a bit like salt, only different!.

To get the elements from the air we need to cool it down to a very low temperature, much lower than even Siberia in winter! At around −190°C it forms a liquid. It's a bit like cooling down steam to make water. Afterwards, by boiling this liquid, the gases are released one at a time. As well as elements Oxygen and Nitrogen, we can get what are called the "Noble Gas" elements Argon, Xenon and Krypton. Two other noble gases, Helium and Neon, are in the air and can be taken out by cooling to an even lower temperature.

You have probably wondered how we have got this far without using some words that you probably have heard, and which are very much part of the subject of chemistry: atom, molecule, electron, nuclear and so forth. In fact, up until about 150 years ago chemists didn't really know very much about any of these things, even though they did understand the difference between elements and compounds.

Today we can "see" atoms by using a special electron microscope, which magnifies things that are millions of times smaller than those things we look at with an ordinary microscope. Under a scanning electron microscope, which shows things in 3-D, atoms appear as fuzzy balls.

Atoms are the key to describing why there exists different elements and why these elements form just those compounds that they do.

Atoms also explain why the Periodic Table of Elements is the way it is, even though much of it was worked out by the old-time chemists like Dobereiner and Mendeleev (see Chapter 4). Understanding atoms can explain, for example, why there are just 81 elements that have atoms which can exist for ever.

Introduction to The Elements

The whole universe is built of matter. Right now, you are surrounded by it. The air we breathe is matter, and all the things you see around you are matter. The odors you smell are matter and the sounds you hear are caused by the movement of matter in your ears.

Matter is everything that takes up space and has weight. Scientists say that matter has volume and mass. Matter is made up of tiny building blocks called atoms. The purest type of atom is called an element. The elements are what give matter its different qualities.

Today we can see atoms by using a special instrument called an electron microscope. An electron microscope lets us see things that are millions of times smaller than the things we can see with a powerful optical microscope.

Most of the matter around us has more than one element in it. But some matter is made up of just one element. If you have ever held a diamond, for example, it is made of just one element, Carbon. Surprisingly, the graphite in a pencil that you use for drawing or writing is also Carbon, just its atoms are differently arranged.

Some other examples of matter that contain just one element are:

• An aluminium drink can
• 24 carat gold
• The helium gas in a balloon that floats upwards
• Cast iron garden railings
• Lead sheeting used by builders on the roofs of houses

NOTE: These examples are not truly pure elements, because metals will always have tiny amounts of other elements present as impurities.

Not many elements occur as a pure substance. Some elements like Gold and Sulphur do naturally occur as a pure substance, as does Carbon when it is a diamond. But most substances are made up of several elements bonded together. For example, water has the chemical formula H₂O meaning that one molecule of water is composed of two hydrogen atoms and one oxygen atom.

Ancient people knew how to extract the element iron from iron oxide. They heated iron oxide dug from the ground with charcoal. The iron was originally a "compound" of two elements, iron and oxygen. By heating them, they separated. The oxygen joined with the carbon in the charcoal leaving the purified iron behind.

The Periodic Table of Elements is a table showing the different kinds of elements arranged according to their different characteristics. Much of it was worked out many years ago. So far we have identified 90 elements that occur naturally. There are approximately 25 more that are man-made. {{:{Wikijunior:The Elements/Matter_Is_The_Stuff_Around_You|Matter}}

The States of Matter

When snow is melting, water is turning from a solid to a liquid form.

There are four main states of matter:

Solids	Solids hold their shape rigidly.	Examples: Blocks, dishes, chairs, pencils
Liquids	Liquids take the shape of their container, but hold themselves together.	Examples: Water, soda, milk, blood
Gases	Gases take the shape of their container completely, spreading apart.	Examples: Air, oxygen, carbon dioxide, steam
Plasmas	Plasmas can act like gases, but are also affected by electromagnetic fields.	Examples: Candle flames, lightning bolts, stars.

Each state is also known as a phase. Elements can change from one phase to another under certain physical conditions. These conditions are temperature and pressure. Temperature is related to the amount of heat a substance has, and pressure is the amount of force "squeezing" the substance. Deep underwater there is high pressure, and atop a mountain there is low pressure.

There is also another state of matter called plasma. It exists on the sun and in fluorescent lights. Plasma is basically a gas that has become electrified.

There are special names for the process of changing from one phase to another:

The phase changes

A substance can change from one phase to another, but still be the same substance. You can see water vapor over a boiling pot of water. That gas can condense and become a drop of water. If you put that drop in the freezer, it would become a solid. No matter what phase it is in, it is always the same chemical: water. It has the same chemical properties. In other words, ice is just solid water, and steam is just gaseous water.

Solids

Solid Basics

Diamonds are the hardest solid forms in nature.

So what is a solid? Solids are usually hard because their molecules have been packed together. The closer your molecules are, the harder you are. Solids also can hold their own shape. A rock will always look like a rock unless something happens to it. The same goes for a diamond. Even when you grind up a solid into a powder, you will see tiny little pieces of that solid under a microscope. Liquids will move and fill up any container. Solids keep their shape.

In the same way that a solid holds its shape, the atoms inside of a solid are not allowed to move around too much. This is one of the physical characteristics of solids. Atoms and molecules in liquids and gases are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in place. The atoms still spin and the electrons will still fly around, but the entire atom will not change position.

Solids can be made up of many things. They can have pure elements or a variety of compounds inside. When you get more than one type of compound in a solid it is called a mixture. Most rocks are mixtures of many different compounds. Concrete is a good example of a man-made mixture.

Crystals

The opposite of a mixture is something called a crystal. When a solid is made up of a pure substance and forms slowly, it can become a crystal. Not all pure substances form crystals because it is a delicate process. The atoms are arranged in a regular repeating pattern called a crystal lattice. A crystal lattice is a very exact organization of atoms.

A good example is carbon. Carbon actually makes more than one kind of crystal lattice, although most elements only make one. A diamond is a perfect crystal lattice while the graphite arrangement is formed into microscopic sheets.

Liquids

Liquid Basics

Water is the most common liquid on Earth, and very common in humans as well.

The second state of matter we will discuss is a liquid. Solids are hard things you can hold. Gases are floating around you and in bubbles. What is a liquid? Water is a liquid. Your blood is a liquid. Liquids are an in-between state of matter. They can be found in between the solid and gas states. They don't have to be made up of the same compounds. If you have a variety of materials in a liquid, it is called a solution.

One characteristic of a liquid is that it will fill up the shape of a container. If you pour some water in a cup, it will fill up the bottom of the cup first and then fill the rest. The water will also take the shape of the cup. It fills the bottom first because of gravity. The top part of a liquid will usually have a flat surface. That flat surface is because of gravity too. Putting an ice cube (solid) into a cup will leave you with a cube in the middle of the cup; the shape won't change until the ice becomes a liquid.

Another trait of liquids is that they are difficult to compress. When you compress something, you take a certain amount and force it into a smaller space. Solids are very difficult to compress and gases are very easy. Liquids are in the middle but tend to be difficult. When you compress something, you force the atoms closer together. When pressure goes up, substances are compressed. Liquids already have their atoms close together, so they are hard to compress. Many shock absorbers in cars compress liquids.

A special force keeps liquids together. Solids are stuck together and you have to force them apart. Gases bounce everywhere and they try to spread themselves out. Liquids actually want to stick together. There will always be the occasional evaporation where extra energy gets a molecule excited and the molecule leaves the system. Overall, liquids have cohesive (sticky) forces at work that hold the molecules together.

Supercooled Liquids

A supercooled liquid is a liquid that is put in conditions where the temperature is dropped below zero very rapidly. The result is that the liquid is still liquid, but acts like a solid. It is hard and cannot have its shape changed easily. Glass used in windows is a supercooled liquid. Normal glass is in fact the liquid form of sand, or silicon dioxide. If a pane of glass was left for hundreds of years, it would eventually start to drip, like normal liquids.

Gases

Looking for a Gas

Most of the gases you encounter daily are invisible, but chlorine is an example of one you can see.

Gases are everywhere. There is something named the atmosphere. That's a big layer of gas that surrounds the Earth, extending from the ground to about 300 miles (480 km) into the air. In solids, atoms and molecules are compact and close together. Particles of liquids are generally a little more spread out. However, gases have no definite volume; they expand as much as they can. Their atoms and molecules are full of energy, bouncing around constantly.

Gases can fill a container of any size or shape. That is one of their physical characteristics. Think about a balloon. No matter what shape you make the balloon, it will be evenly filled with the gas's particles. The atoms and molecules are spread equally throughout the entire balloon. Liquids can only fill the bottom of the container, while gases can fill it entirely.

Compared to liquids and solids, gases can also be compressed with relatively little pressure. It happens all the time. Combinations of pressure and decreasing temperature force gases into tubes that we use every day. You might see compressed air in a spray bottle or feel the carbon dioxide rush out of a can of soda. Those are both examples of gas forced into a space smaller than it would want, and the gas escapes the first chance it gets.

You might hear the term vapor. Vapor and gas mean the same thing. The word vapor is used to describe substances that are normally liquids at room temperature, but are currently in their gas form. Compounds like carbon dioxide that are gases at room temperature don't need the term, so scientists will rarely talk about carbon dioxide vapor. Water and mercury are liquids at room temperature, so they're called water vapor and mercury vapor after they're changed to a gas.

Plasma

A plasma Lamp

The fourth state

Plasma is known as the fourth state of matter and is in fact the most common state of matter. Over 99% of the matter in the universe is plasma. It is in the form of an excited gas. Plasma is created when the gas gets so hot that the electrons are stripped away from the atoms, giving it a positive charge.

A candle flame is plasma.

Examples of Plasma

One common example of a plasma is the flame of a candle. The candle wax burns and gives off a hot gas that emits energy, in the form of light. It is this excited and hot flame that is known as plasma. All fire is plasma. The light we see during a lightning strike is plasma. Another example of plasma is the sun and other stars. The light and heat of the sun is a result of hydrogen and other elements in a plasma state.

Uses of Plasma

Argon gas in a plasma state interacting with the phosphor coating within a glass tube gives us fluorescent lighting. Neon signs use argon in a plasma state interacting with mercury and phosphorus to produce their bright colors. Another example is the plasma television which works by applying electricity to cells of xenon, neon, and helium gas between two plates of glass. When the electricity is applied to the cells the gasses become plasma and interact with different phosphors to form the colors we see on the screen.

Gas laser systems, for example Helium/Neon types, use the two inert gases in a hot and excited state to emit large bursts of light energy.

Some specialised welding apparatus use a plasma of inert gas to prevent the metals from oxidising (by excluding oxygen from the surrounding air) while being welded.

Solutions

Solutions and Mixtures

Forming a solution of table salt in water. When completely dissolved, the salt crystals can no longer be seen, but the water will taste salty.

Before we dive into solutions, let's separate solutions from other types of mixtures. Solutions are groups of molecules that are mixed up in a completely even distribution. Not the easiest way to say it. Scientists say that solutions are homogenous systems. Other types of mixtures can have a little higher concentration on one side of the liquid when compared to the other side. Solutions have an even concentration throughout the system. An example: Sugar in water vs. Sand in water. Sugar dissolves and is spread throughout the glass of water. The sand sinks to the bottom. The sugar-water could be considered a solution. The sand-water is a mixture. No matter how hard you stir, the sand will not disappear into the water the way the sugar will.

Can Anything Be In Solution?

Pretty much. Solutions can be solids dissolved in liquids. They could also be gases dissolved in liquids (such as carbonated water). There can also be gases in other gases and liquids in liquids. If you mix things up and they stay at an even distribution, it is a solution. You probably won't find people making solid-solid solutions in front of you. They start off as solid/gas/liquid-liquid solutions and then harden at room temperature. Alloys with all types of metals are good examples of a solid solution at room temperature. A simple solution is basically two substances that are combined, called the solute and the solvent. The solute is the substance to be dissolved (sugar). The solvent is the one doing the dissolving (water). As a rule of thumb, there is usually more solvent than solute.

Making Solutions

So what happens? How do you make that solution? Mix the two substances and stir. It's that simple. Science breaks it into three steps. When you read the steps, remember... Solute=Sugar, Solvent=Water, System=Glass.

1. The solute is placed in the solvent and the concentrated solute slowly breaks into pieces.

2. The molecules of the solvent begin to move out of the way and they make room for the molecules of the solute. Example: The water has to make room for the sugar molecules.

3. The solute and solvent interact with each other until the concentration of the two substances is equal throughout the system. The concentration of sugar in the water would be the same from a sample at the top, bottom, or middle of the glass.

Can Anything Change Solutions?

Sure. All sorts of things can change the concentrations of substances in solution. Scientists use the word solubility. Solubility is the ability of the solvent (water) to dissolve the solute (sugar). You may have already seen the effect of temperature in your classes. Usually when you heat up a solvent, it can dissolve more solid materials (sugar) and less gas (carbon dioxide). Next on the list of factors is pressure. When you increase the surrounding pressure, you can usually dissolve more gases in the liquid. Think about your soda can. They are able to keep the fizz inside because the contents of the can are under higher pressure. Last is the structure of the substances. Some things dissolve easier in one kind of substance than another. Sugar dissolves easily in water; oil does not. Water has a low solubility when it comes to oil.

Mixtures II

There are a few more words you might hear when people talk about mixtures. We can't cover all of them, but we'll give you a quick overview of the important mixtures.

Alloys

A gladiator medallion of bronze, which is an alloy known by man since ancient times.

Alloys are basically a mixture of two or more metals. Don't forget that there are many elements on the periodic table. Elements like calcium and potassium are considered metals. Of course, there are also metals like silver and gold. You can also have alloys that include small amounts of non-metallic elements like carbon. Metals are the key thing to remember for alloys.

The main idea with alloys is that they are better at something than any of the metals could be alone. Metallurgists (people who work with metals) sometimes add chromium and/or nickel to steel. While steel is already an alloy that is a very strong metal, the addition of small amounts of the other metals help steel resist rusting. Depending on what element is added, you could create Stainless Steel or Galvanized Steel. It's always about improving specific qualities of the original. Another good example of an alloy happens when metallurgists add carbon to steel. A tiny amount of carbon (a non-metallic element) makes steel stronger. These special carbon-steel alloys are used in armor plating and weapons.

Amalgams

Amalgams are a special type of alloy. Anyway, amalgams are alloys that combine mercury and other metals in the periodic table. You might know mercury as "quicksilver" or the metal that is liquid at room temperature. The most obvious place you may have seen amalgams is in old dental work. The fillings in the mouths of your grandparents may have been amalgams. We already talked about mercury's being a liquid at room temperature. That physical trait was used when they made fillings. Let's say you have an amalgam of mercury and silver. When it is created, it is very soft. As time passes, the mercury leaves the amalgam and the silver remains. The silver that is left is very hard. Voila! You have a filling!

NOTE: Never, ever, play with mercury! It is very poisonous. You shouldn't even touch it because it will seep into your skin. Dentists don't usually use amalgams with mercury anymore because it may have slowly poisoned people and gotten them sick.

Emulsions

These special colloids (another type of mixture) have a mixture of oils and waters. Think about a botttle of salad dressing. Before you mix it, there are two separate layers of liquids. When you shake the bottle, you create an emulsion. As time passes, the oil and water will separate to their original states.

Overview

Atoms Around Us

Everything in the Universe is made of matter. All matter is made of tiny particles called atoms. Atoms are so incredibly tiny that trillions of them could fit into the period at the end of this sentence.

If you want to have a language, you will need an alphabet. Chemistry is no different. If you want to build molecules, you will need elements. Each element is a little bit different from the rest. Those elements are the alphabet to the language of molecules.

Let's stretch the idea a bit. If you read a book, you will read a language. Letters make up that language. But you need ink to create the letters on the page, and for each letter, it is the same type of ink.

Elements are like those letters — and atoms are like the ink they're written in. Each element is a particular kind of atom (a particular shape for the ink), and each atom is always an element (the ink is always in the shape of a letter).

While the atoms may have different weights and organization, they are all built in the same way. Electrons, protons, and neutrons make the universe go.

If you want to do a little more thinking, start with particles of matter. Matter, the stuff around us, is used to create atoms. Atoms are used to create the elements. Elements are used to create molecules. It just goes on. Everything you see is built using something else.

You could start really small...

-Particles of matter

-Atoms

-Elements

-Molecules

-Macromolecules

-Cell organelles

-Cells

-Tissues

-Organs

-Systems

-Organisms

-Populations

-Communities

-Ecosystems

-Biomes

-Biospheres

-Planets

-Planetary Systems with Stars

-Galaxies

-Galaxy Clusters

-The Universe

... And finish really big.

All of that is possible because of atoms.

Structure

In the center of this model of a helium atom is the nucleus. (Not drawn to scale)

Protons, neutrons and electrons make up atoms. Because of this, they are called subatomic particles. Each type of atom can differ in the number of protons, neutrons, and electrons. According to the current electron cloud theory of atoms: there are two parts to the atom, the nucleus and the electron cloud. The nucleus is made up of protons and neutrons, and in turn each of these nucleons is made up of triples of even smaller particles called "quarks".

The nucleus is the center of the atom and contains the protons and neutrons. The nucleus is very small compared to the size of the electron cloud. This means there a massive amount of empty space around the nucleus. The protons and neutrons of an atom are in specific locations. Both protons and neutrons have a mass of about 1 amu (atomic mass unit) each. The atomic mass of an atom is thus the sum of the number of protons and neutrons. (Electrons are thousands of times lighter, so they aren't part of the calculation.)

The protons have a positive charge. The number of protons decides what element an atom is. For example, if an atom has one proton, that means it is a hydrogen atom; only hydrogen can have one proton. On the periodic table, the atomic number of the element is the same as its number of protons.

The neutrons have no charge, but they help stabilize the nucleus; if the positive charges of the protons were by themselves in the nucleus, they would repel each other and make the nucleus less stable. Atoms of the same element but with different numbers of neutrons called isotopes of each other. For example, hydrogen has three natural isotopes, one with no neutrons, one with one neutron, and one with two neutrons. They all have one proton and so they are all hydrogen, but because they differ in the number of neutrons they are different isotopes. Some isotopes are radioactive, which means that they decay, or release over time. A certain radioactive isotope of carbon, called carbon-14 (carbon with an atomic mass of 14) is used by paleontologists to discover the age of fossils. They can do this because they know the rate at which carbon-14 decays.

The outer part of the atom, the electron cloud, surrounds the nucleus. According to a theory called quantum mechanics, we never know the exact location or speed of a specific electron; we can only say the probability of it being anywhere. If we know exactly where the electron is, we don't know how fast it is going. If we know how fast it is going, likewise, we cannot determine where exactly it is located. An electron has a negative charge that is as powerful as a proton's positive charge. Some scientists used to think that electrons orbited the nucleus like planets around the sun, but we now know this isn't true. The electrons move somewhat randomly around the nucleus and are attracted to the positive charge of the protons in the nucleus.

Atoms = Building Blocks

Atoms are the basis of chemistry and everything in the Universe. You should start by remembering that matter is composed of atoms. Atoms and the study of atoms are a world unto themselves. We're going to cover basics like atomic structure and bonding between atoms. As you learn more, you can move to the biochemistry tutorials and see how atoms form compounds that help the biological world survive.

Electron Arrangement

This Bohr model shows an atom of barium, which has six energy levels. The energy level closest to the nucleus is the first energy level.

Electrons are organized in energy levels.

Energy level	Electron capacity
First	2
Second	8
Third	18
Fourth	32
Fifth	50
Sixth	72

The energy levels don't have to be full for electrons to be in a higher energy level. For example, titanium has an electron configuration of 2-8-10-2. That means it has 2 electrons in the first energy level, 8 in the second, 10 in the third, and 2 in the fourth.

As explained before, some atoms only have a certain amount of electrons, so some elements don't have as many energy levels with electrons as others.

The outermost energy level is called the valence energy level. Likewise, electrons in the outermost energy level are called valence electrons. These electrons help atoms combine into molecules.

References

DNA is a very complicated molecule and essential for all known life.

What is a molecule?

A molecule is the smallest thing that a substance can be divided up into, while remaining the same substance. It is made up of two or more atoms held together by chemical bonding. These atoms can be the same kind, or different kinds. This is slightly different to a compound, where it has to be two or more atoms of different elements. This does mean that all compounds are molecules, but not all molecules are compounds.

Where do we find molecules?

Almost everything is made up of molecules, including the air you breathe, the food you eat, and even the water you drink! In the air, oxygen atoms usually travel with a partner (2 x O = O₂), as does hydrogen (2 x H = H₂) and nitrogen (N₂). Water (H₂O) is made of two hydrogen atoms (H₂) and one oxygen atom (O). Even regular table salt that you eat is a combination of molecules! Would it surprise you to know that the molecules in table salt are made up of dangerous atoms? You may eat salt every day, but it is made up of an explosive atom (sodium) and a toxic one (chlorine)! The reason salt is safe to eat is that molecules are very different from the atoms that make them up.

How do the atoms join together?

Atoms come together to form molecules because of their electrons. Electrons can join (or bond) atoms together in two main ways. When two atoms share electrons between them, they are locked together (bonded) by that sharing. These are called covalent bonds. Bonds like this are in oxygen gas, nitrogen gas, and hydrogen gas. But when an atom gives one of its electrons to another atom, they are held together by electric forces. These sorts of bonds are called ionic, because once an atom loses or gains an electron, it becomes something called an ion, which has a positive or negative charge. These sorts of bonds are in acids, like vinegar, and bases, like ammonia. Salt is also held together by ionic bonds. The sodium, usually explosive, loses an electron to the chlorine, which is also dangerous in its natural state, but when this reaction happens, both become harmless and even tasty!

Bonding

Atoms are able to bond to each other to make molecules and compounds. A compound is a molecule with more than one kind of element in it. How do they do it? It has to do with their electrons.

Ionic Bonds

When an atom is by itself before it has reacted with anything, it has the same number of protons as it has electrons. With an equal number of protons and electrons, the charges cancel each other out and the atom has no charge.

Sometimes, atoms do not have an equal number of protons and electrons. If an atom loses an electron, that means it has more protons than electrons, and so the atom has a positive charge. If an atom gains an electron, that means it has more electrons than protons, and so the atom has a negative charge. Atoms with a charge are called ions.

To form an ionic bond, some atoms will take an electron from another atom; this will make both of them ions, one positive and one negative. Because one is positive and one is negative, the ions will attract to each other and form an ionic bond. An ionic bond is a bond formed when one atom takes the electron or electrons of another atom.

Covalent Bonds

Not all bonds are formed by taking electrons away. Atoms can share electrons instead. By sharing electrons, atoms can bond together, but they do not form ions because none of the atoms lost or gained electrons.

Pure Covalent Bonding

This is when the two atoms that form the bond share the electrons equally.

All atoms can attract electrons in a pure covalent bond. Some have high attracting powers, like oxygen, nitrogen, chlorine, and fluorine. Some have low attracting powers like metals, carbon, and hydrogen. Elements with identical or similar attraction are considered to form pure covalent bonds.

Polar Covalent Bonding

This involves unequal sharing. The further right and up the Periodic Table, the greater the attracting powers of the element. The exceptions to this are the noble gases. If two elements have significant differences in attracting powers, the result is a Polar Covalent Bond.

Metallic bonds

A slightly different form of sharing that can be thought of in terms of atoms sitting in a sea of shared electrons. Metallic bonds exist only in metals, such as aluminum, gold, copper, etc.

• alchemy: a science that attempts to change one element into another.
• alloy: a substance that is a mixture of two or more metals.
• amalgam: any metallic alloy that has mercury in it.
• atom: any one of the smallest particles of an element that has the chemical properties of the element. Atoms are neutral, being neither positive nor negative by having the same amount of electrons and protons.
• chemical bond: a bond (like covalent or ionic bonds) between atoms or ions that forms a molecules.
• chemical substance: a substance that is made of only one type of molecule.
• chemistry: the science of the properties, composition, and transformation of substances.
• compound: a special type of molecule that is made up of at least two different elements.
• condensation: the changing of a gas to a liquid.
• conductive: able to pass heat or electricity from one side to the other.
• corrosion: the act of eating away at gradually, as by rust or chemical action.
• covalent bond: a bond between atoms formed by sharing of electrons.
• deposition: the act of changing a gas directly to a solid.
• ductile: capable of being drawn out into threads, as some metals.
• electron: a negatively charged particle that is a component of all atoms. Electrons are approximately organized in shells. They are also as negative as protons are positive.
• element: a natural substance which cannot be broken down any further by chemical processes.
• emulsion: a liquid, as milk, in which minute particles remain in suspension.
• fusibility: the ability to join separate parts together as one.
• gas: a fluid and elastic form of matter tending to expand indefinitely.
• halogens: elements that have seven valence electrons, all of which are very reactive.
• ion: An ion is an electrically charged particle. Some atoms can bond with each other ionically to form molecules. Certain atoms are allowed to have certain ionic charges so that they may bond with other atoms having opposite ionic charges.
• ionic bond: a bond between ions.
• liquid: a compressed mass of particles that flow freely.
• luster: how much a material shines.
• malleable: capable of being hammered or shaped without breaking.
• matter: any substance that has mass and volume.
• melting: the process of converting a solid to a liquid, usually by adding heat to the solid.
• metal: one of the elements with the characteristics of luster, ductility, malleability, fusibility, and conductivity of heat and electricity.
• mixture: two or more different substances that are put together but still retain their own properties. An example is salt and pepper.
• molecule: a particle formed by two or more atoms that are chemically bonded together that therefore has new properties not necessarily possessed by the components. An example is a water (H₂O) molecule, which is made of the explosive hydrogen and oxygen.
• neutron: an uncharged particle having slightly more mass than a proton. It is located in the nucleus of an atom.
• nucleus: the center of an atom. It contains all the protons and neutrons in the atom.
• ore: a mineral in its natural state.
• oxide: a compound that contains oxygen and at least one other element.
• particle: a very tiny piece, such as an electron, atom, or molecule.
• proton: a positively charged particle in the nucleus of an atom. Protons are as positive as electrons are negative.
• radioactive: A radioactive substance releases particles like beta particles (electrons from the nucleus) over time. Eventually, most of the substance will have changed into a different element.
• solid: a form of matter that resists changes to both shape and volume.
• solution: a mixture of solids, liquids, and/or gases that joins together evenly.
• sublimation: the act of changing a solid directly to a gas.
• valence electron: an electron that is on the outer-most shell.
• vaporization: the changing of a liquid to a gas.

The_Elements

== Aluminum ==

Shows the position of Aluminum on the periodic chart.

Aluminum's symbol on the Periodic Table

Aluminum, also known as aluminium, is a metal that is very light. Aluminum is used in many industries to make lots of things. It is very important to the world economy.

What does it look, feel, taste, and smell like?

A piece of aluminum metal.

Aluminum is a soft, lightweight metal which usually has a dull silvery appearance. This dull appearance is caused by a thin layer of oxidation that forms quickly when the metal is exposed to air. Without this layer of oxidation, aluminum has a bright and clear silvery appearance. It feels very soft and it is odorless.

Who discovered aluminum and how?

Sometimes there can be disagreement about who discovered something, even when all the facts are known. Friedrich Wöhler is credited with isolating aluminum in 1827 by mixing anhydrous aluminum chloride with potassium. The metal, however, had indeed been produced for the first time two years earlier — but in an impure form — by the Danish physicist and chemist Hans Christian Ørsted. Therefore, Ørsted can also be listed as the discoverer of the metal.

Where did its name come from?

In 1807, Sir Humphry Davy was trying to isolate aluminum from a mineral called alumina. He first called the metal alumium, but decided to call it aluminum in 1812.

Did You Know?

• Recycling aluminum requires one twentieth as much energy as producing aluminum from raw ore.
• Aluminum is the most common metal in the earth's crust.
• Aluminum and Aluminium are two different names for the same metal.

Where is it found?

Aluminum is the most abundant metal in the Earth's crust, and the third most abundant element overall, after oxygen and silicon. But it is not found free in nature. The Bayer process is used to refine aluminum from bauxite (aluminum oxide), an aluminum ore.

What are its uses?

147,000 pounds of aluminum are used in building a single Boeing 747 airplane.

Aluminum has many uses. It is light and strong. Aluminum helps us get from place to place since it's a part of cars, trucks, airplanes, bicycles, rockets, and more.

Every morning you wake up and look in a mirror, the reflective backing is likely made from aluminum. The pots and pans your family uses to cook dinner may be made with aluminum. The utensils you eat your dinner with could be made with aluminum, along with the kitchen aluminum foil used to wrap up leftover food. Soda cans are also made from aluminum.

When aluminum is combined with iron oxide (Fe₂O₃) in the right quantity, thermite can be made. Thermite burns very quickly and with extreme heat, which is why it's often used to cut or weld steel objects, such as railway tracks. Aluminum is one of the primary components of the fuel that propels rockets into space.

Is it dangerous?

Aluminum isn't dangerous. The metal is protected by a surface layer of aluminum oxide. This surface layer forms at once when the metal is exposed to air, and is very stable. So dishes, pots, and pans can be made of aluminum, and aluminum foil can be used for packing sensitive foods. However, acidic foods, such as tomatoes, can dissolve the surface oxide layer and some of the aluminum underneath. This isn't dangerous and doesn't compromise the strength of the aluminum object, but can lead to off tastes in the food, which is why it is usually not recommended to cook acidic foods in aluminum cookware.

External links

== Antimony ==

Shows the position of Antimony on the periodic chart.

Antimony's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Antimony in its pure form.

Antimony is a brittle, bluish silver-white metalloid. It has no smell. It also has no odor at all. Antimony is toxic to humans, so we unfortunately can't taste it!

How was it discovered?

Antimony was known to the ancients. The discoverer and the date when it was discovered are both unknown. During the early 1700s, French chemist Nicolas Lemery was the first person to perform a scientific study of antimony and its compounds. His findings were published in 1707.

Where did its name come from?

The name "antimony" comes the combination of two Greek words: anti (meaning against) and monos (meaning solitude). When combined, the two words mean "not alone". You can remember the chemical symbol for Antimony, which is Sb, by remembering "Susan B Anthony" who was a US women's rights activist.

Did You Know?

• Antimony, in the form of stibnite, was used by the ancient Egyptians as black eyeshadow.
• Antimony has metallic and nonmetallic properties. It is a metalloid.
• Antimony is resistant to attack by acids.

Where is it found?

Antimony can be found free in nature, it is usually derived from the ores stibnite (Sb₂S₃) and valentinite (Sb₂O₃). A small amount of the earth's crust, 0.000002%, is made up of antimony.

What are its uses?

Antimony is used for hardening lead. Antimony is also used in the production of plastics and chemicals. Alloys of antimony are used to make products such as: batteries, low-friction metals, type metal and cable sheathing. Compounds of antimony are used to make flame-proofing materials, paints, ceramic materials, glass and pottery.

Is it dangerous?

Antimony is extremely dangerous. It was once used to kill parasites and is deadly in many of its compounds.

References

== Argon ==

Shows the position of Argon on the periodic chart.

Argon's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Argon has no smell. It is a colorless gas. It has no taste. It, being inert, is non-toxic.

How was it discovered?

Argon was discovered by Lord Rayleigh and Sir William Ramsay in 1894. It was isolated by examination of the residue obtained by removing nitrogen, oxygen, carbon dioxide, and water from clean air. In fact, air contains slightly less than 1% argon, making it the third most abundant gas in air, behind nitrogen and oxygen. The atmosphere of Mars contains less than 2% argon. It was recognized by the characteristic lines in the red end of the spectrum.

Where did its name come from?

The name Argon comes from argos, the Greek word for lazy or inactive. It got this name, because it doesn't react easily with other elements.

Did You Know?

• Argon is heavier than air.
• Argon is the third most abundant gas in air.
• Argon forms only one compound.

Where is it found?

Argon is found in the air and is a byproduct of the production of oxygen and nitrogen. Argon makes up .93% of the Earth's atmosphere.

What are its uses?

Canisters containing Argon gas for use in putting out fire without damaging server equipment

Argon can be used to make light signs

Argon can be used to put out fires without damaging electronics. Argon is used in welding arcs and growing semiconductor crystals. Argon is also used in some light signs. Light signs containing argon emit a deep blue light. In some double-glazed windows, argon is contained to slow the loss of heat. For the same purpose some diving suits are also filled with argon for those diving deep down where it's freezing cold. Argon can protect an object stored in it by forcing out the water vapours and oxygen that would damage the object like the Magna Carta.

Is it dangerous?

Argon is usually not dangerous; it can be inhaled safely as long as there is also oxygen.

References

== Arsenic ==

Shows the position of Arsenic on the periodic chart.

Arsenic's symbol on the Periodic Table

Arsenic is a poisonous metalloid.

What does it look, feel, taste, or smell like?

Elemental arsenic

The most stable — and therefore the most common — form of pure arsenic is gray. There are also yellow and black forms. Yellow arsenic is the most unstable and the most toxic.

How was it discovered?

Compounds of arsenic have been known since ancient times — arsenic sulfates, and arsenic oxides. Pure arsenic is rare in nature. As far as we know, the first person to isolate pure arsenic was Albertus Magnus, a German friar and bishop, around the year 1250 CE.

Where did its name come from?

The Greek word arsenikos, meaning "male", "virile" was adopted in Latin as arsenicum, which in French became arsenic, from which the English word arsenic is taken.

Did You Know?

• Arsenic has metallic and nonmetallic properties. It is a metalloid.
• Arsenic comprises about 1.5 ppm (0.00015%) of the Earth's crust.
• Arsenite of lime and arsenate of lead were used widely as insecticides until the discovery of DDT in 1942.

Where is it found?

Arsenic is a fairly common element on Earth. A lot of it is mined in China. Other countries that mine a fair amount of arsenic are Chile, Peru, and Morocco.

What are its uses?

Arsenic is used in some alloys to make them harder. It was sometimes used in ancient times to make bronze harder. It is also used in some pesticides, although these are not used as much as they used to be because of concerns it could hurt people if it gets on their food.

Is it dangerous?

Arsenic is poisonous. It is used in pesticides and other poisons.

References

== Barium ==

Shows the position of barium on the periodic chart.

Barium's symbol on the Periodic Table

Barium is a chemical element with the symbol Ba and atomic number of 56. It is also a member of the alkaline earth metals.

1.5 grams barium

What does it look, feel, taste, or smell like?

Barium is a soft metallic element, which looks silvery white and has no smell when it is pure.

How was it discovered?

A shoemaker named Vincentius Casciorolus learned about the heavy, silvery-white mineral which was impure barium sulfate (BaS04). He noticed that after being heated up, this mineral would change into unusual pebbles that glowed for years. He named these pebbles "Bologna stones", and they were later determined to be barium sulfate. Then, barium was first discovered in barite by German chemist Carl Scheele and English chemist William Withering in the late 18th century.

Where did its name come from?

Barium gets its name from the Greek word “barys", which means heavy. It received the "ium" part of its name by Sir Humphry Davy, who used it to show how it is a metallic element.

Did You Know?

• Hydrogen gas is released when barium reacts exothermically with water.
• Barium makes up only 0.0425% of the Earth’s crust.
• Breathing in pure barium can irritate the lungs.
• Barium creates a dark gray coating when it is oxidized in air.
• Barium is commonly alloyed with metals such as aluminum. 

Where is it found?

Barium has a high chemical reactivity. As such, it is never found naturally in its pure form. In nature, it reacts with water to form barium hydroxide, and oxygen to form barium oxide.

What are its uses?

Barium is used to color fireworks green. It can also be used to help create a vacuum in television tubes by removing unwanted gas from the tube.

Is it dangerous?

Barium can't dissolve in water, but it can dissolve in our stomachs. This can result in the bodies heart rate changing.

External links

== Beryllium ==

Shows the position of Beryllium on the periodic chart.

Beryllium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

More than 99 % pure crystalline Beryllium

Beryllium has a sweet taste to it, but due to its toxicity it should never be eaten or sampled. It has no odor. It is grey, and light-weight.

How was it discovered?

Beryllium was found by Louis-Nicolas Vauquelin in 1798. Vauquelin found beryllium in beryl and emeralds.

Where did its name come from?

The name came from the Greek word for pale because the gemstone beryl is pale.

Where is it found?

It is found rarely in isolation in the earth. It is found in 30 mineral species including: Terlandite, Beryl, Chrsoberge, and Phenacite. It is found in large quantities in old stars. This was discovered in 1992 where scientists found a lot of beryllium in 6 old stars on the edge of the Milky Way.

What are its uses?

Did You Know?

• It is not known to be useful or necessary for plant or animal life.
• It usually used as hardening for metals.
• It does not rust at room temperature.

Because beryllium is one of the lightest metals and has one of the highest melting points of light metals, it has been used in structures for high speed aircraft and missiles. Because it also does not spark, it is used in non-sparking tools. Because it reacts with the alpha particles released by polonium to produce neutrons, it is used in A-bomb initiators. And finally, because it does not react with acid and uranium it is used to make nuclear generators.

Is it dangerous?

It is toxic, from moderate-high risks of health problems such as lung cancer, Chronic Beryllium Disease, and etc. Can also cause various skin problems.

References

== Bismuth ==

Shows the position of Bismuth on the periodic chart.

Bismuth's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

A bismuth crystal. The bottom edge is about 3.5cm (about 1.4 inches).

Bismuth is a soft brittle, heavy, pinkish-tinged silver metal that tarnishes easily in air. The crystal form gives off a reflection of rainbow-like colors. The smell is undetermined.

How was it discovered?

Bismuth was used for centuries without people knowing what it was, and they confused it with tin or lead. In 1753, Claude François Geoffroy showed that it was neither tin nor lead but an element in its own right.

Where did its name come from?

Bismuth comes from the Latin bisemutum, which itself comes from the German Wismuth, apparently meaning "white mass". That's a reference to a material mass and not to a religious service.

Did You Know?

• Bismuth is the heaviest element that isn't strongly radioactive.
• It forms beautiful crystals.
• It's about twice as common as gold.

Where is it found?

It's found in many places, but usually in ores of elements more valuable than bismuth. The bismuth is separated from the other elements.

What are its uses?

Pure bismuth isn't very useful even if it is pretty.

It's heavily used in soldering -- that is, putting two pieces together with a molten metal that then cools and binds the two metal objects. Some of its alloys are used in printing type, as some of its special combinations with other metals melt at low temperatures for metals and can easily be re-used. Some of it appears (with other metals)in fire alarms. It also appears in very common medicines, including some intended to settle an upset stomach. Where lead cause trouble because it is poisonous (like sinkers for fishing), people are now often using bismuth instead.

Is it dangerous?

A fine powder of the metal can burn.

Most bismuth compounds are safe unless they are strongly acidic or contain something otherwise toxic. But you don't want to get too much of them. With any medicines, follow directions carefully.

It is very slightly radioactive -- but so slightly radioactive that it is less radioactive than some of the carbon and potassium in your cells, and its radioactivity does no real harm.

References

== Boron ==

Shows the position of Boron on the periodic chart.

Boron's symbol on the Periodic Table

Boron

General:

Boron is a chemical element. Boron’s atomic number is 5, and its symbol is B. Boron belongs to the metalloid category of elements on the periodic table. The periodic table arranges chemical elements into periods (rows) and groups (columns). Boron is in period 2 and group 13.

Boron sometimes conducts electricity like a metal. It is classified as a semiconductor.  Semiconductors are also known as metalloids. Metalloids have properties that are in between those of a metal and a nonmetal. Other elements that are classified as metalloids are silicon, germanium, arsenic, antimony, and tellurium.

What does it look, feel, taste, and smell like?

Boron has no distinct feel, odor, or color. Boron compounds may have a slight odor and a slightly sweet or bitter taste.

There are two forms of boron. One is made of extremely hard black crystals. Its atoms and molecules are arranged in an orderly way. It is known as crystalline boron. The other form of boron is a brown powder. The atoms and molecules of the powdered form are disordered and shapeless.  

Is it dangerous?

Exposure to small amounts of boron is not dangerous. However, ingesting large amounts can cause nausea and vomiting. Boron dust can irritate the delicate lining of the lungs. Contact with boron compounds can cause skin and eye irritation.

Where does its name come from?

The word “borax” comes from both Arabic and Persian languages. The Arabic term is  buraq meaning “white”; the Persian term is burah.

How was it discovered?

Tourmaline-Quartz

Boron was first discovered in France in 1808, by Joseph-Louis Gay-Lussac and Louis-Jacques Thenard. They combined boric acid with potassium. The result was a gray solid they named bore. In England, Sir Humphrey Davy used a similar method to discover boron around the same time.  

Where is it found?

Pure boron is not found naturally on Earth. It exists in minerals called borates. The minerals borax and kernite are sources of boron. These minerals are found in arid, dry regions where there were once ancient lakes. There are borate mines in California’s Mojave Desert. There are borate mines in Turkey, China and India.

What are its uses?

For people, boron has important health benefits. It makes strong bones and helps with brain function.

For plants, boron is needed for pollination, root growth, and flowering. Inside a plant, boron keeps cells and membranes strong and stable. It helps to move sugar and energy to growing parts.

Egyptians and Romans used borax for cleaning and preserving food. Today, borax is used for household cleaning and laundry. It is an ingredient in “slime” recipes for kids’ crafts. Boron compounds are used to make toothpaste, lotion, and sunscreen. Boric acid is used in insecticides, flame retardants, antiseptics, and other useful compounds. Boric oxide is used in heat resistant cookware such as Pyrex™.

Brown-powder boron is used to create green flames in fireworks. Boron carbide is an extremely hard substance nicknamed “black diamond”. It is used in making tank armor and bullet-proof vests.  

References

Britannica kids. (2024). Boron boron - Students | Britannica Kids | Homework Help

Cirino, E. (2023, June 19). Is borax toxic? Healthline. https://www.healthline.com/health/is-borax-safe

Curtis, L. (2023, September 21). Sodium borate: Is it safe? And how it differs from the mineral boron. Verywellhealth.

https://www.verywellhealth.com/sodium-borate-509193

Ducksters. (2024). Chemistry for Kids: Elements - Boron. https://www.ducksters.com/science/chemistry/boron.php

Encyclopedia.com. (n.d.). Sodium tetraborate. https://www.encyclopedia.com/science/academic-and-educational-journals/sodium-tetraborate

Helmenstine, A. (2019, February 6). Boron Chemical & Physical Properties. Boron's Chemical and Physical Properties (thoughtco.com)

JLab Science Education. (n.d.). The periodic table of elements.  The element boron. https://education.jlab.org/itselemental/ele005.html

Kiddle Encyclopedia. (2023, October 16). Chemical compounds facts for kids. https://kids.kiddle.co/Chemical_compound

Kiddle Encyclopedia. (2023). Semiconductor Facts for Kids. Semiconductor Facts for Kids (kiddle.co)

Smith, M. (2022, August 20). Borax. WebMD. https://www.webmd.com/a-to-zguides-borax-sodium-tetraborate

Thoughtco.com. Understanding phosphorous, boron and other semiconductor materials.

Updated by M. Bellis, September 24, 2018  Retrieved June 1, 2024.

Understanding Phosphorous, Boron and Other Semiconductor Materials (thoughtco.com)
== Bromine ==

Shows the position of Bromine on the periodic chart.

Bromine's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Bromine is a toxic, reddish-brown liquid at room temperature. It has a very strong odor that can irritate the eyes, lungs, and throat. It is hard to describe the smell but most people say that it smells like chemicals.

How was it discovered?

25 milliliters of bromine, a liquid at room temperature

Bromine was discovered independently by Antoine Balard and Carl Jacob Löwig in 1825 and 1826. Balard produced it from seaweed ash and Löwig isolated bromine from a mineral water spring near his home.

Where did its name come from?

The name "bromine" comes from the word brôme, which derives from the Greek βρωμος (stench.)

Did You Know?

• Bromine is an ingredient in the rare purple dye shellfish, or Tyrian, purple, the cost of which was what made the color purple synonymous with royalty.
• After fluorine, bromine is the most reactive element.
• Bromine is a reddish-brown liquid at room temperature and it the only liquid non-metal.

Where is it found?

Bromine exists exclusively as bromide salts in the Earth's crust, and as the bromide ion in seawater.

What are its uses?

Bromine compounds are used as flame retardants, pesticides, and as additives in leaded gasoline.

Is it dangerous?

Yes, it is toxic. Bromine should not make any contact with skin. When it contacts skin, bromine produces painful sores. Inhalation may lead to death.
== Carbon ==

Shows the position of Carbon on the periodic chart.

Carbon's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Diamonds and graphite (the stuff that pencil leads are made of) are both made of carbon.

Did You Know?

• Carbon has the highest melting point of all of the elements at 3652 °C(6605 °F).
• Most molecules known to science contain carbon.
• Carbon is one of the four main elements in most or all living things (the others are hydrogen, oxygen, and nitrogen.)
• When carbon is heated to a very high temperature it sublimates (changes directly from a solid to a gas).

How carbon looks depends on the molecule shape carbon makes. Carbon has many allotropes (see Wikipedia article). The most famous type of carbon shape is diamond. Diamond is clear but very shiny. It is very valuable and the hardest substance from nature. It is number 10 on the Mohs scale of hardness. Low quality diamonds can be made from other forms of carbon. Diamond is also notable for being one of the few substances which conducts heat very well but does not conduct electricity.

Another well known type of carbon is graphite, which is used in pencils. Graphite is grey instead of clear, and very soft, registering about 1 on the Mohs scale of hardness.

How was it discovered and how did it get its name?

Carbon was known prehistorically by ancient people who produced it in the form of charcoal. The name is based on the Latin name carbo, which means charcoal.

Where is it found?

Carbon is found in many places. Diamonds, graphite, and oil all contain carbon and can all be found underground. Carbon is also present in all living things, in organic molecules such as fat and sugar. Carbon is also found in the atmosphere as part of carbon dioxide and other compounds. Organic chemistry is a branch of chemistry that is dedicated to studying carbon-containing compounds. Some scientists speculate that without carbon, life couldn't exist at all. Others suggest that life based on silicon is possible.

A racing car. The body of the car is made from steel, it burns petroleum, and it drives on asphalt. All of these substances contain carbon. The person driving the car has carbon as one of the three most important constituent elements of his (or her) body. The car also releases carbon dioxide (the air you breathe out) into the atmosphere as it burns petroleum.

What are its uses?

Diamonds are often used as decorations and in jewelry. Because diamonds are so hard, they are sometimes used to make blades to cut things, but these blades are very expensive. Graphite is very soft. Because of this, it is often used in pencils. "Lead" pencils are actually carbon.

Carbon separates the oxygen from iron in iron ore in furnaces and allows the useful metal iron to be made. Much carbon is used in making iron. When carbon is heated with iron in a furnace, steel is made.

When carbon is combined with hydrogen it forms a molecule called a 'hydrocarbon'. Hydrocarbons are very important because they are used for energy and fuel. Petroleum, such as the gas in your car, is a hydrocarbon and it is used to power vehicles and to make lubricants, among other things.

Carbon is sometimes used in filtration as "activated carbon", and helps to clean some unwanted materials from water.

When carbon is laid out into a 2-D sheet, it becomes a type of carbon called graphene. Graphene might be used to make computers in the future.

Is it dangerous?

Carbon is relatively safe by itself. However, inhaled soot or smoke, which contain carbon, are bad for your lungs. Carbon is part of carbon dioxide which is linked to global warming. Incomplete burning of hydrocarbons releases carbon monoxide, which is very dangerous because it keeps the hemoglobin in your blood from picking up oxygen and basically suffocates your cells, so try not to breathe in the exhausts from your car.

References

== Calcium ==

Shows the position of Calcium on the periodic chart.

Calcium's symbol on the Periodic Table

What does it look and feel like?

Calcium is a soft, gray metal. When it burns, it burns with a yellowish-red flame. When it is exposed to air, it develops a gray-white coating because it reacts with the oxygen in the air to form a coating of calcium oxide (lime.)

Strongly alkaline and reactive with any body fluids such as sweat, calcium metal burns flesh exposed to it. Do not touch it.

How was it discovered?

Calcium has been known since Ancient Roman times. The Romans discovered a way to make calcium oxide by heating limestone in a furnace. However, it wasn't until 1808 that pure calcium was isolated by Sir Humphrey Davy.

Where did its name come from?

Calcium gets its name from calcis, which is a Latin word that means lime.

Did You Know?

• As wet calcium hydroxide combines with air it becomes hard calcium carbonate. This chemical reaction is what causes cement to harden.
• Calcium is the most common metal in animals.
• Stalactites and stalagmites are made primarily of calcium carbonate.

Where is it found?

Calcium is not found pure as an element due to its great tendency to react with other elements to form compounds, but it is commonly found in the compound calcium carbonate (CaCO₃). Many rocks such as limestone, marble, chalk, and calcite contain this substance. Limestone caves are a great example of where calcium can be found. Seashells and snail shells are primarily of calcium carbonate. Eggshells are mostly made from this compound too.

Calcium is also found in significant amounts in many foods. Dairy products like milk, yogurt and cheese contain calcium. Green vegetables also often have calcium. Broccoli, collard greens, almonds, sesame seeds, and beans all contain significant amounts of calcium.

The Hoover Dam is made of cement. Calcium is the element that causes cement to harden.

What are its uses?

Calcium is important for our body to run. It helps build strong bones and teeth, and it allows our muscles and brain cells work.

Calcium is an important substance in the building industry, because calcium hydroxide (Ca(OH)₂ is used in cement and mortar. Calcium carbonate is also used in plastics and adhesives as a filler. Because calcium oxide (CaO) neutralizes acid it can be used to decrease the effects of acid rain in rivers and lakes. Calcium is also commonly used in heartburn and antacid tablets.

Is it dangerous?

Calcium metal burns hot if ignited, and it reacts violently with water to form the strongly-alkaline calcium hydroxide that can cause chemical burns.

Calcium compounds aren't dangerous unless they are strongly alkaline or acidic or if they are poisonous due to the other parts of the compound. Calcium compounds are nearly everywhere in our bodies. In fact, calcium is an essential nutrient that is needed by the human body to help build strong bones and teeth.

Calcium metal has a very high boiling/melting point.

External links

== Cerium ==

Shows the position of cerium on the periodic table.

Cerium's symbol on the Periodic Table

The cerium element in the lighter created the spark shown

What does it look, feel, taste, or smell like?

Cerium is a rare earth element (REE) group (in the Lanthanide series). It looks like a soft, silver-grey METAL and it’s very malleable. It tarnishes when exposed to air. It’s very reactive. It is also the most common element in the rare earth elements group. Cerium and mischmetal fires have a distinct smell that has both a metallic and smoky quality.

How was it discovered and where?

It was discovered by two Swedish scientists named Jöns Jakob Berzelius and Wilhelm Hisinger in 1803. It was discovered in Bastnäs, in Sweden.

Where did its name come from?

It was named after the asteroid Ceres which was discovered in 1801. A fun fact is the asteroid was discovered two years before the element “Cerium” was found out.

Did You Know?

• Humphry Davy invented electrochemistry which help scientists to isolate the cerium from other elements
• About 0.0046% of the weight of Earth’s crust is composed of cerium.
• The named Cerium came from the asteroid named Ceres. The asteroid was discovered about two years before the humans welcomed the element into human life.

What are its uses?

Cerium can have two roles in being used:

This is the picture of cerium oxide. It must mix with warm water to become a liquid to make the glass shiny again.

1.5 grams of Ultrapure cerium under argon

1) Cerium oxide is used to make the glass shiny again.

2) Cerium metal is used for making ferrocerium lighters. Ferrocerium lighters have a flint spark lighter that produce a little spark after the fire has been lit.

Is it dangerous?

It is dangerous because it is highly reactive with water and produces hydrogen gas during the reaction. Also it will ignite if it is scratched with a sharp object, such as a knife. BUT it can be safe if used or mixed with other elements.
== Cesium ==

Shows the position of Cesium on the periodic chart.

Cesium's symbol on the Periodic Table

Cesium metal

What does it look, feel, taste, or smell like?

Cesium is a silvery-gold color. It is a soft alkali metal, with a very low melting point — 28C, which is below human body temperature (37C).

How was it discovered?

It was discovered in 1860 by two German chemists, Robert Bunsen and Gustav Kirchhoff. They discovered it in mineral water from a spa in Germany, using a spectroscope — which they had discovered the previous year.

Where did its name come from?

Did You Know?

• It is liquid at or near room temperature.
• It has been widely used in highly accurate atomic clocks.
• The largest application of cesium has been as cesium formate for drilling fluids

Bunsen and Kirchhoff named this element after the color of the light they observed from it with their spectroscope. The Latin word caesius means bluish-gray.

What are its uses?

Cesium plays a role in getting oil to run your car and power your home. It can be used in some forms of oil drilling, acting as a lubricant and maintaining pressure.

Cesium binds well with oxygen and other gases, so it is also helpful in making vacuum tubes in order to remove the remaining oxygen from the tubes.

When used as a coating on cathode tubes, it can increase the electric current.

Is it dangerous?

Cesium burns when it comes in contact with the air and vigorously explodes when exposed to water.

References

== Chlorine ==

Shows the position of Chlorine on the periodic chart.

Chlorine's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

This beaker contains table salt which is made from sodium and chlorine

Chlorine as an element is a pale green, poisonous gas with a suffocating odor. Chlorine as a chemical cleaner (in a solution with water) is a liquid, which is colorless with little odor, and a distinctly chemical taste. Chlorine can cause a burning sensation on the skin.

How was it discovered?

Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele.

Where did its name come from?

Chlorine gets its name from the Greek word chloros, which means "pale green".

Did You Know?

• Rock salt was used as early as 3000 BC and brine as early as 6000 BC.
• Chloride, the ionic form of Chlorine, is the most abundant dissolved substance in seawater.
• Nearly all elements in the periodic table form binary chlorides.
• Elemental chlorine is commercially produced from brine by electrolysis,

Where is it found?

In nature, chlorine is mostly found as chloride, the ionic form of chlorine. Chloride is very common in seawater as part of sodium chloride, the scientific name for salt. In a laboratory, chlorine gas can be generated by the rapid combination of a strong base and a strong acid, or by running electricity through a solution of table salt (which is NaCl, the most common salt in seawater and the best-known, and probably the most common, chlorine compound n the world.)

Chlorine is used in swimming pools to kill bacteria.

What are its uses?

Chlorine is commonly used to purify water so it is clean enough to bath in. Almost all public pools use chlorine as a cleaning chemical for water. Chlorinated water can be toxic at high concentrations. Chlorine as a gas is incredibly dangerous, and has been used as a chemical weapon. Chlorine is also used in bleaches.

Is it dangerous?

Yes, when chlorine is concentrated in a gaseous form, it is extremely toxic to humans, killing within minutes of exposure. The gas burns lungs when it is inhaled, and victims of inhalation most often die of a combination of asphyxiations and internal bleeding from damage to the airways.

External links

== Cobalt ==

Shows the position of Cobalt on the periodic chart.

Cobalt's symbol on the Periodic Table

General: Cobalt is a chemical element. Cobalt belongs to the transition metals category of elements on the periodic table. The Periodic Table arranges chemical elements into rows (periods) and columns (groups). Cobalt is number 27 on the table. Chemical elements are represented by symbols. The symbol for cobalt is Co.

What does it look, feel, taste, or smell like?

Pure (99.9 %) cobalt chips, electrolytically refined, and a high purity (99.8 % ) 1 cm3 cobalt cube for comparison.

Cobalt appears solid with a silvery-grey luster and bluish tinge. It remains hard and brittle at room temperature and has a bluish-white color. It is one of the few elements that is naturally magnetic.

Cobalt and its compounds could be toxic, so touching or tasting would be unsafe.

Cobalt does not have a distinct smell. It is reported that the compound cobalt chloride smells like wet cardboard, and cobalt sulfate smells like rotten eggs.

Is it dangerous?

Although it is needed for good health, too much or too little cobalt in the body can cause health issues.

The heart, eyes, and skin can be harmed by prolonged exposure to cobalt. Lung problems can be caused by breathing cobalt dust.

Where did its name come from?

Did You Know?

• Cobalt has been used to color glass since the Bronze Age.
• Cobalt is a ferromagnetic metal.

The term cobalt comes from the German word kobold, meaning goblin. Medieval miners believed the kobolds caused toxic vapors to be released when cobalt ore was heated. Instead, the toxic vapors came from heating arsenic, which is commonly found with cobalt.  

How was it discovered?

Georg Brandt, a Swedish chemist, discovered cobalt in 1735. He was interested in a blue pigment called smalt. It was used to color glass, ceramics, and pottery. It was known as blue sand in ceramics and royal blue in artists’ pigments. Smalt was sometimes known as powder blue when it was used for “bluing” linens to make them appear whiter.  

People thought the element bismuth made the blue color of smalt. Brandt determined it was a different element not yet discovered that made the smalt blue. He found the new element and named it cobalt after the German word kobold. Brandt proved that cobalt was the element in smalt that made the blue coloring in glass, ceramics, and fabrics.

Cobalt was the first metal to be discovered that was not an ancient metal like iron, copper, or gold. Georg Brandt is recognized as the first person in history to discover a new metal.

Where is it found?

Cobalt occurs in very small quantities in air, water, food. soil, rocks, and plants. Cobalt is found in ores, minerals, and chemical compounds in the Earth's crust. Miners often find cobalt alongside copper, nickel, and other ores inside mines.

Cobalt ore deposits are found in China, Russia, and Africa. The United States imports cobalt from other countries.

Cobalt is a “critical raw material” because there are few places where it can be mined in large quantities. It is in very high demand all over the world.

What are its uses?

Cobalt has many uses in the areas of the arts, health, industry, and medicine. It is used in arts and crafts to make pigments of many colors for glass, ceramics, paints, and ink. It plays an important role in keeping the body healthy. It is used in making batteries, magnets, and airplane parts.  

References

ChemTalk. (n.d.). The coy element cobalt. https://chemistrytalk.org/cobalt-element/

Ducksters. (n.d.). Elements for kids Cobalt. https://www.ducksters.com/science/chemistry/cobalt.php

Ducksters. (n.d.). Elements for kids transition metals. https://www.ducksters.com/science/chemistry/transition_metals.php

Greenleaf, J. (2023, August 11). Smalt. https://www.greenleafblueberry.com/blogs/news/pigment=histoies-smart-pb32

Jervois Idaho Cobalt Operations. (n.d.). Idaho cobalt belt. https://jervoisidahocobalt.com/idaho-cobalt-operations/

Mount Siani Health System. (n.d.). Cobalt poisoning. https://www.mountsinai.org/health-library/poison/cobalt-poisoning

Rana, D. (2023, July 11). Cobalt. Learnool. https://learnool.com/cobalt/

Royal Society of Chemistry. (n.d.). Cobalt. https://www.rsc.org/periodic-table/element/27/cobalt
== Copper ==

Shows the position of Copper on the periodic chart.

Copper's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Native copper about 1 ½ inches (4 cm) in size.

A small stream and lake with copper dissolved in it

Copper is a reddish-orange metal, one of only two metals (the other being gold) which has a color other than silver or gray. It tastes metallic, and feels like salt.

How was it discovered?

As early as 10,000 years ago, people found small deposits of native (pure) copper metal in the ground. This copper was then hammered and used to make weapons, tools and decorations. In Northern Iraq, a copper pendant was found that can be dated back to about 8700 B.C.

Where did its name come from?

Copper gets its name from the Latin word Cuprum, meaning from the island of Cyprus. In the Ancient Roman world (whose common language was Latin), most copper was mined in Cyprus.

Did You Know?

• Copper used to be the symbol for the Roman goddess Venus, to whom the island of Cyprus was sacred.
• The Statue of Liberty contains 179,200 pounds (81.3 tonnes) of copper.
• When a form of copper dissolves in water, the water turns blue.

Where is it found?

Copper can be found underground in the form of copper ore. The main copper ore producing countries are Chile, United States, Indonesia, Australia, Peru, Russia, Canada, China, Poland, Kazakhstan, Zambia, Zaire, and Mexico. Copper is usually obtained from the ores cuprite (CuO₂), tenorite (CuO), malachite (CuCO₃.Cu(OH)₂), chalcocite (Cu₂S), covellite (CuS), and bornite (Cu₆FeS₄).

What are its uses?

In many countries, such as the United States and Canada, pennies are made at least partly from copper.

As copper is a great conductor of electricity it is used to make wires that carry electricity into homes, schools and businesses. In addition, copper is used to make locks, pipes, doorknobs, pots, bronze and jewelry. Most coins also contain copper, not just pennies (in fact pennies are now mostly zinc due to rising copper prices, but other coins are mostly still copper.)

Is it dangerous?

A little copper is necessary for many living things. However, copper in higher levels can be toxic if eaten.

References

== Einsteinium ==

Shows the position of Einsteinium on the periodic chart.

Einsteinium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Einsteinium is a metal that can glow in the dark due to its radiation. The people who had seen it said that it is soft and silvery with no smell. Its symbol is Es.

How was it discovered?

Einsteinium was discovered by Albert Ghiorso and his team at Lawrence Berkeley National Lab (USA) in 1952 while studying the leftovers of the first hydrogen bomb. It was discovered along with fermium (Fm).

Where did its name come from?

Einsteinium is named after the physicist Albert Einstein. This is why its symbol is Es.

Did You Know?

• Einsteinium the first element with two bonding electrons in the actinide series.
• Einsteinium has no natural isotopes.
• Before the name “Einsteinium”, it was named as “Athenium” after Athens, the capital of Greece.

Where is it found?

Einsteinium is very hard to find and produce. We can find einsteinium in the remains of nuclear bombs. Einsteinium is formed when some uranium atoms capture some neutrons and go through decay steps. Since einsteinium does not occur naturally, we can only find a small amount of it.

What are its uses?

Einsteinium has no particular uses due to the small amount of production. It’s only used for basic research by the scientists and for creating other metals.

Is it dangerous?

Einsteinium is radioactive and is considered highly dangerous. Einsteinium is also very reactive with halogens and chalcogens. Einsteinium has not been found in the earth's crust, so there's no need to consider its environmental hazards, but it could cause harm due to its radiation.

References

== Fluorine ==

Shows the position of Fluorine on the periodic chart.

Fluorine's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Fluorine is usually a pale yellow gas. It has a pungent odor. It is far too dangerous to taste or feel.

How was it discovered?

Henri Moissan

Henri Moissan isolated pure fluorine in 1886. Many other scientists had unsuccessfully tried to isolate fluorine from hydrogen fluoride. In some cases they accidentally killed themselves by exposure to dangerous compounds. Moissan's successful method relied on electrolysis — using an electric voltage to convert fluoride ions to fluorine gas. He won the Nobel Prize in 1906 and died the next year at the age of 54.

Where did its name come from?

Fluorine gets its name from the Latin word fluere, which means "to flow". Fluorspar ores were used as fluxes, which help ores to flow during smelting. Fluorine was later found to be a present in fluorspar.

Did You Know?

• Fluorine is the most reactive element.
• Fluorine is the 13th most abundant element in the earth's crust.
• Fluorspar ores can look either like emeralds or amethyst. Fluorine's atomic number is 9

Where is it found?

Fluorine is so reactive that it is not found in its elemental state. It is always found bonded to a different element. Some common minerals from which fluorine can be extracted include fluoroapatite, cryolite, and hornblende. There are currently no working mines in the US that produce fluoride ores. The last one closed in 1995, so fluorine is imported into the US.

What are its uses?

Fluorine is not used much in the elemental form because it is so reactive. One use is in rocket fuel, where elemental fluorine is used in place of oxygen to help fuels burn.

Fluoride, the ionic form of Fluorine, is put in toothpaste and sometimes in water to help prevent cavities in the teeth.

3D model of Teflon

Teflon, the non stick material found in frying pans, is a polymer that is 75% fluorine by weight. The scientific name for Teflon is polytetrafluoroethene, or PTFE. This is a chain of carbon atoms with two fluorine atoms attached to each carbon atom.

Fluorine is used in hydrofluoric acid in industry. The acid is able to dissolve silicate-containing compounds such as glass and computer chips. Because of this it cannot be stored for a long time in glass containers. The acid is used for cleaning, purification, and etching.

Fluorine can react with uranium to produce uranium hexafluoride. This compound is then centrifuged to separate out the different isotopes of uranium. This is how enriched uranium is obtained.

A major use of fluorine was in the production of CFCs, the chemicals that lead to the ozone hole. These were once common in aerosols and cooling fluids, but have been banned in developed countries in accordance with the Montreal Protocol.

One of the more interesting compounds of fluorine is sulfur hexafluoride, a gas that, unlike most fluorine compounds, is safe to handle. It was long used as a propellant, a gas used to drive others in a spray. Unfortunately it is a strong greenhouse gas and is very limited in its possible uses.

Is it dangerous?

Fluorine and some of its compounds are highly toxic

Fluorine gas is extremely poisonous. It can cause chemical burns on the skin. Hydrofluoric acid is very dangerous. It causes burns to the skin like sulfuric acid and other acids do, and is also easily absorbed into the skin. Once inside the body it causes damage to tissues and organs. Exposure of less than 2% of the body to concentrated hydrofluoric acid can be fatal. The small levels of fluoride ions in toothpaste and treated water are not dangerous, although slightly higher levels can cause unsightly (and permanent) mottling of the teeth.

References

Web Links

Webelements

The Discovery of Fluorine and Fluoride

Within Wikipedia

Fluorine

Henri Moissan
== Francium ==

Shows the position of Francium on the periodic chart.

Francium's symbol on the Periodic Table

What does it look, feel, taste or smell like?

Francium is a very unstable metal. Francium is thought to have a silvery and gray color to it. No one has tasted francium because francium is very rare and it would kill you.

How was it discovered?

Francium was discovered in 1939 by Marguerite Perey of the Curie Institute, in Paris, France.

Where did it name come from?

Because there is so little naturally occurring francium on earth, francium can be produced by bombarding thorium with protons or by bombarding radium with neutron

It is named after France. It was originally to be called "Catium" but it was decided against this as English speakers would possibly associate it with cats (the animal).

What are it uses?

Francium has a short half-life of about 22 minute and it is so unstable, it would decompose to other elements so quickly that there are no uses for francium based on the research of francium

Is it dangerous?

Francium is highly radioactive. Francium would react violently to water, air and halogens.

Did You Know?

• At first, francium had a symbol of Fa but later it became Fr
• Francium is the most unstable of the first 101 elements of the periodic table
• Francium is the second rarest element in the Earth’s crust, next to astatine

== Gallium ==

Shows the position of Gallium on the periodic chart.

Gallium's symbol on the Periodic Table

What does it look and feel like?

Crystals of 99.999% gallium.

Gallium is an odorless, soft, silver metal. Its melting point is low, around 37 degrees Celsius, so it can be melt when you hold it. Gallium is such a soft matter that it can be cut, using a normal knife easily. You can shape it if you like even with your hand. When you put it in acids and alkalis, it will react.

How was it discovered?

Paul E. Lecoq who is a French Chemist, found Gallium through a spectroscope in 1875 in Paris.

Where did its name come from?

Paul E. Lecoq de Boisbaudran, the chemist discovering that element, named it “Gallium” . Gallium is a Latin word which means France.

Where is it found?

Did You Know?

• • Gallium is easy to change the state and it depends on the temperature.
  • The Gallium will melt when you put it out of your hand. Your body temperature will make the gallium melt.
  • This Gallium does not react with oxygen and air or water because the oxide layer.

Gallium is not found in and its elemental form on earth but it is found in minerals and ores on earth.

What are its uses?

Gallium is used like silicon and it’s an important substance in electronics industry. It is also useful in making thermometers because it has low melting point like mercury but non toxic, which is better than mercury.

Is it dangerous?

When Gallium dissolves into aluminium, it will release ability to create a protective oxide layer. If it happens, any metal machines will be collapsed , injuring or killing people. It is banned from planes in case the metal could damage any metal things in the plane.

References

== Gold ==

Shows the position of gold on the periodic chart.

Gold's symbol on the Periodic Table

A French chalice (cup) 800 years old. It shows many ways that gold can be worked.

Gold is a yellow precious metal that is valued for its beauty and shine. Gold is softer than many other metals and can be formed into different shapes using simple tools and without fire or other heat. Because it can be found in clumps and is easy to work, it is believed to be the first metal that was used by humans. It has been used for making coins and jewelry for thousands of years. Today it is still used to make jewelry. Because it is a rare metal, it is a symbol of wealth. It is also used in electronic devices such as computers.

Gold may be worked into all sorts of shapes. It can be rolled into tiny shapes. It can be pulled into thin wire, which can be twisted and plaited. It can be hammered or rolled into sheets. It can be made very thin, and stuck onto other metal. It can be made so thin that it was sometimes used to decorate the hand-painted pictures in books called "illuminated manuscripts".

Gold does not "react" with many other chemicals. This means that it does not lose its shine, or rust, or burn, or explode. When ancient gold coins or jewellery are found, they look as shiny and beautiful as the day they were made.

Where did its name come from?

Gold gets its English name from the Germanic word gulþa (meaning gold). The Old English word geolu means yellow. In Latin, gold was called aurum. This is why the chemical symbol for gold is Au.

Where is it found?

Gold is rare, which means it is difficult to find. Gold is usually found underground, where it is dug out of mines that are tunnelled deep into the earth. Gold is usually found as thin layers in rocks, but is also sometimes found in lumps. A lump of gold is called a nugget.

Gold can sometimes be found above the ground in the sand and gravel bars of streams. Flakes and grains of gold that are trapped in rock come loose as the rock is broken up by the force of the water. The water then carries the gold downstream. When the stream slows down, the gold settles along with sand and gravel. People sometimes look for loose gold in streams, or in places where streams have once flowed. This is called "prospecting". A prospector often carries a wide pan, to scoop up the sand and gravel from the bottom of a stream and swish it around, looking for tiny flakes and nuggets of gold. This is called "gold panning".

Gold is used to coat the visor of space suits in order to protect the astronaut's eyes from infrared radiation.

Is it dangerous?

Gold is not dangerous. Very pure gold leaf (sometimes called "edible gold") is safe to eat and is sometimes used to decorate food. Gold is so safe to put in your mouth that many people have false teeth and fillings made of gold. Sometimes gold has "impurities". This means that small amounts of different elements are in the gold. The impurities in the gold may be poisonous.

Did You Know?

• Gold was probably the first metal used by humans.
• Gold is so soft that people used to bite gold coins to make sure they were real.
• A single gram of gold can be pounded into a sheet of gold leaf covering a square meter.

== Helium ==

Shows the position of Helium on the periodic chart.

Helium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Helium's Atom is very simple

Helium is seen on earth as a colorless and odorless gas. It is the clearest element, and even in a liquid state (which can only be achieved by either applying great pressure or extreme cold) it is almost completely transparent. However, in a plasma state (see below,) it emits a pinkish glow.

Helium in a plasma state.

A monument to helium doubles as a time capsule including thousands of items packed in helium in Amarillo, Texas. Much of the world's helium is mined in the area.

How was it discovered?

Helium was discovered in the Sun in 1868 by an astronomer, Sir Norman Lockyer. He was using a technique (then new) called spectrography, which breaks light into its separate colors. Each element produces a different spectral pattern of bright lines. Lockyer noticed a line in sunlight that didn't match any known element and realized it belonged to a new element not found on Earth.

About 27 years later, in 1895, Sir William Ramsay discovered helium on Earth in a uranium mineral, cleveite. It was discovered independently about the same time by P.T. Cleve and Nils Langlet.

Where did its name come from?

Helium gets its name from Helios, the Greek god of the sun.

Did You Know?

• Helium is the second most common element in the universe.
• Helium is a noble gas, so it doesn't react very easily.
• Helium was used to learn that the structure of the atom had a dense nucleus and an electron cloud.
• Even at absolute zero, helium is still a liquid. It can only be solidified by applying extreme pressure to liquid helium.
• Near absolute zero, liquid helium will crawl along any surface; this is called superfluidity. Superfluid helium has zero viscosity (thickness.)

Where is it found?

Helium is found very commonly in the universe, but not very common on Earth. Today, most helium comes from Texas and Kansas in the United States. It is extracted along with natural gas from wells drilled into the ground.

A Zeppelin blimp filled with helium.

What are its uses?

Helium is used to inflate balloons and blimps because it is the second lightest element (after Hydrogen), but doesn't burn like Hydrogen can.

Helium is often used (along with oxygen and sometimes nitrogen) in breathing gas for divers that go very deep, where high pressure is needed. (Normal air at this pressure causes nitrogen narcosis, a state similar to being drunk.)

Liquid helium is the coldest liquid known (even at absolute zero, it remains a liquid) and is often used in cryogenic applications such as Magnetic Resonance Imaging (MRI), where the extreme cold makes it possible to create extreme magnetic fields.

Is it dangerous?

Though helium is nontoxic, if you breathe in too much helium you can suffocate through lack of oxygen.

External links

== Hydrogen ==

Shows the position of Hydrogen on the periodic chart.

Hydrogen's symbol on the Periodic Table

Hydrogen is an atom that contains an electron and a single proton. It is found at the very upper left of the periodic chart. The symbol for Hydrogen is the letter H. Hydrogen is both the lightest and most abundant element in the universe. Here is some data:

• Name: Hydrogen
• Symbol: H
• Atomic Number: 1
• Atomic Mass: 1.00794 amu
• Melting Point: -259.14 °C (14.009985 K, -434.45203 °F)
• Boiling Point: -252.87 °C (20.280005 K, -423.166 °F)
• Number of Protons and Electrons (same number): 1
• Number of Neutrons: 0
• Classification: Non-metal
• Color: Colorless

What does it look, feel, taste, or smell like?

A close up of the Rosette Nebula. Stars are forming in this region of space. The red color comes from clouds of hydrogen.

Hydrogen is the absolute smallest of all elements, so small that four billion atoms, laid end to end, could fit on the head of one pin! At room temperature, hydrogen is a clear gas. Hydrogen gas (H₂) is a molecule made of two hydrogen atoms bonded together. It has no taste or odor and is not toxic. It takes a very, very low temperature and/or very high pressure to turn hydrogen into a liquid or a solid. One common molecule formed by hydrogen is water, or scientifically known as H₂O. It has two hydrogen atoms and one oxygen atom. At room temperature, water is a clear liquid.

How was it discovered?

Henry Cavendish was the first to understand that hydrogen was a unique substance. In 1776, he produced hydrogen by mixing mercury with an acid. Hydrogen had actually been produced much earlier by the Swiss alchemist Paracelsus. He also added mixes of water samples in it to make water!

Where did its name come from?

Hydrogen comes from Hydrogenes, which comes from Ancient Greek meaning "water-forming". The element was named by Antoine Lavoisier in 1783. When hydrogen burns, it produces water.

Did You Know?

• Hydrogen is the smallest element.
• Hydrogen is the most abundant element in the universe.
• Hydrogen isn't common in a pure form on Earth, but is mostly found as part of water.
• Hydrogen is the main fuel of stars and the only fuel for red dwarfs.
• Hydrogen makes a squeaking noise when it is set on fire.

Where is it found?

Hydrogen in its atomic form is found commonly in space and stars. There are vast clouds of hydrogen in outer space. However much of the hydrogen in space is missing an electron, which means it is an ion. On Earth, hydrogen is commonly found as part of water molecules. Very little of it is in our atmosphere though, as it is so light that it can simply float to space! Many other molecules also contain hydrogen, such as propane and plastics. Some bacteria produce pure hydrogen gas as waste.

The Sun setting into the sea. The Sun is mostly hydrogen. Most of the hydrogen on Earth is in the form of water.

Hydrogen is very important for all living creatures including people to exist. It is found in every living thing on Earth, and also forms the oceans, rivers, lakes and clouds.

Hydrogen gas makes up most of the atmospheres of the gas giant planets Jupiter, Saturn, Uranus, and Neptune, which are massive planets in our solar system that have much stronger gravity and lower temperatures than Earth.

What are its uses?

The largest application of hydrogen is for the processing ("upgrading") of fossil fuels, and in the production of ammonia. Hydrogen can be used as a fuel source by burning it for heat or by using hydrogen fuel cells. A fuel cell is a device that produces electricity by safely combining hydrogen and oxygen.

Hydrogen is lighter than air, which allows it to rise. If it is put into a container such as a balloon, it can lift it very high! In the past, it was used to lift many airships, which are massive balloon-like vehicles that were used to transport people long distances, like we use planes for nowadays. Unfortunately, it is much less safe than Helium, which isn't flammable, so it is very rarely used for that purpose nowadays.

In the future, non-polluting cars may be fueled by hydrogen. The technology to make a hydrogen car already exists, but there are reasons you don't see them on the road. Separating hydrogen from water takes energy. The energy needed to produce enough hydrogen to power a car can cause pollution. Also, it's hard to carry enough hydrogen to power a vehicle for a long trip.

Stars give off light and heat because of the energy made when hydrogen atoms are merged (or fused) together to form heavier elements. Scientists are working to create a reactor that can make energy in the same way. This, however, is a very hard problem to solve and will take many years before we see useful fusion reactors built.

Is it dangerous?

Elemental hydrogen is highly flammable, and when it is mixed with oxygen gas or with air it can burn or even explode. The Hindenburg Disaster was caused by this property, as the ship was filled with hydrogen instead of helium. When it caught fire, the ship was quickly engulfed in flame as the hydrogen inside quickly ignited and took the entire ship down. This terrible disaster could have been avoided if helium was used to lift it instead, but helium was very rare and expensive at the time so the airship's builders were forced to use hydrogen instead.

While not toxic, hydrogen isn't safe to breathe alone, as it cannot take the place of the oxygen that our bodies need to survive. As long as it's mixed with enough normal air, it's perfectly safe to breathe and it can even raise the pitch of your voice if you inhale some!
== Iodine ==

Shows the position of Iodine on the periodic chart.

Iodine's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Purple-pink iodine vapour in a flask.

Iodine is a dark grey or purple solid. It can sublimate into a purple-pink gas that has an irritating odor.

The solid iodine is a dark, almost black, grey or purple color.

How was it discovered?

Iodine was discovered by Barnard Courtois in 1811 by accident.

Where did its name come from?

Iodine gets its name from the Greek word iodes, which means purple. It is a purple element in both the solid and gas phase.

Where is it found?

Iodine is mostly found in seawater as iodide (I^-). Seaweed and kelp can absorb iodide and store it, making it easy to harvest.

Did You Know?

• Iodine changes directly from a solid to a gas at room temperature (this is called sublimation).
• Although many people think of iodine as a dark bluish liquid, it's actually a purple solid.

What are its uses?

Iodine is necessary as part of the diet of many organisms. This is because it is part of thyroid hormones produced by the thyroid gland in your neck. Not consuming enough iodine causes a condition called goiter, where the thyroid gland grows abnormally (so, ironically, does consuming too much iodine.) We "iodize" salt by putting iodine in it, converting some of the salt to sodium iodide (NaI), so that we can get the proper amount of iodine in our diet.

A solution of iodine is also used to kill bacteria when someone gets a cut.

Finally, iodine can be used to test for the presence of starch, because starch turns dark blue when it combines with iodine.

Is it dangerous?

Elemental iodine is dangerous and poisonous. Do not touch it.

References

== Iron ==

Shows the position of Iron on the periodic chart.

Iron's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Casting iron. People pour melted iron into a mold.

Iron is shiny and metallic with a gray tinge. It is solid and heavy. As it oxidizes (rusts) it becomes a distinctive reddish brown.

Iron is usually a solid, and it needs to be extremely hot to melt. In fact, it melts at one and a half thousand degrees. This temperature is even hotter than the hottest part of a candle flame! To melt it, engineers and scientists have to use a torch called a welding torch. This torch melts iron, and it can be used to stick two pieces of iron together. When iron is melted, it glows red. It is literally 'red hot'.

How was it discovered?

Iron has been known to people since ancient times. It is believed that people have been using iron for at least 5,000 years.

Where did its name come from?

The modern English word iron comes from the old English word isærn, which comes from Indo-European roots meaning "strong metal" or "holy metal". (In ancient times, anything strong was considered holy, and they used the same word.) Some linguists like the "holy metal" origin since the first iron used came from meteorites that fell from the sky so were thought to have been provided by the gods. But others suggest it comes from "strong metal" since iron is much stronger than the bronze which was used before the Iron Age.

Iron's chemical symbol, Fe, comes from "ferrum", the Latin word for iron. To this day, metals that contain iron are known as 'Ferrous' metals.

Did You Know?

• Iron is created in massive stars before they explode in a supernova.
• Iron is the second-most abundant metal in the Earth's crust, behind only aluminum.
• The ion Fe2+, inside a heme group in a molecule of hemoglobin, allows blood to carry oxygen.
• The Earth's magnetic field is generated by the movement of molten iron in the outer core.

Where is it found?

Iron makes up about 5% of the Earth's crust and a large part of the Earth's core. Iron also comes from meteorites.

On earth Iron is found mainly inside the minerals hematite (Fe₂O₃) and magnetite (Fe₃O₄.) Removing the iron from these minerals is a reasonably long process involving many large industrial factories. During this process many other elements are used in order to remove the iron, including limestone and carbon.

What are its uses?

The Golden Gate Bridge with traffic. The bridge is made of more than 83,000 tons of steel and supported by huge steel cables. The cars on the bridge are made from steel too.

Iron is used in a lot of alloys such as cast iron, wrought iron, steel, and carbon steel. There are many useful things made of steel including cars, trucks, ships, trains, rails, cutlery, bridges, and all kinds of different machines . In fact, there are few machines that do not use steel. Steel beams are used to reinforce large cement structures like skyscrapers and make them stronger.

Iron is an essential part of hemoglobin, which carries oxygen in red blood cells. Iron also aids with the production of chlorophyll in plants. Iron is also used in iron sulfate (FeSO4), a treatment for the blood disease anemia.

Is it dangerous?

Some types of iron are dangerous to the body in large amounts. However, the intestines do not absorb that much iron, so iron poisoning only happens if there is so much iron that the intestines are damaged, or if the iron is injected. It can also be dangerous if a large chunk of it falls on your head.

References

== Krypton ==

Shows the position of Krypton on the periodic chart.

Krypton's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Krypton is an odorless and colorless gas.

How was it discovered?

It was discovered on May 30, 1898 by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist. They discovered it by boiling liquified air and some of the liquid that was left was Krypton. Due to Krypton's (relatively) high boiling point at -153.415 C, the more abundant gases or low boiling point gases evaporated and what was left was Krypton.

Krypton element form

Where did its name come from?

The name comes from the Greek word kryptos, which translates to English as hidden.

Where is it found?

The only source for Krypton is the Earth’s atmosphere. It is believed that the Earth’s atmosphere is around 0.0001% Krypton gas.

What are its uses?

Krypton gas discharge tube

Krypton is used as a filling gas in fluorescent light. It is also used for flash lamps and high speed photography. It can also be used for lasers and was also used in the Cold War to measure Soviet nuclear production.

Is it dangerous?

Krypton is an odorless and colorless gas. Since it is a noble gas, it is inactive. Noble gases barely react to anything, so they are not considered dangerous. The only gas Krypton reacts to is Fluorine which creates Krypton Difluoride.

References

== Lead ==

Shows the position of Lead on the periodic chart.

Lead's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

A sample of lead solidified from the molten state

Lead is a soft, heavy metal. When freshly cut it is bright silver in color, but it tarnishes in the air to a dull grey. It is a soft and malleable metal. It does not have an odor.

How was it discovered?

Lead has been used for at least 7000 years. There have been lead pipes from Roman times found today.

Where did its name come from?

In Latin, lead was called plumbum; in Rome, lead was used for plumbing. This is why the symbol for lead is Pb. The English word lead comes from the German word lot, which means "weight". Lead is very heavy and is commonly used in weights.

Where is it found?

Lead is usually found in ores, like galena (which is lead sulfide, PbS.)

Did You Know?

• Pencil "lead" has never been made out of lead; instead, it is made out of graphite, a form of carbon.
• Lead was associated with the planet Saturn.
• The word "plumbing" comes from the Latin word for lead, plumbum.

What are its uses?

Lead providing a shield to block radiation.

Lead has high density (it is very heavy for its size) and fairly inexpensive, so it is commonly used to make weights such as fishing sinkers and dumbbells. It is also used to make bullets and other ammunition. Its high density also makes lead an effective shield to block radiation. For example, before taking dental x-rays the technician will put a lead apron over the patient's body to prevent unnecessary radiation exposure.

Because lead melts at a fairly low temperature, it is mixed with other metals to make solder, used to join pipes or electrical wires. But lead solder is being replaced with other types of solder that are safer and better for the environment (such as silver solder, which contains silver instead of lead, or brazing, which uses pure copper metal.)

Lead was used in some paints to make it dry faster and last longer. However, the dust that naturally comes off of painted walls is toxic when it contains lead, so leaded paint is no longer used for painting houses (but older buildings with leaded paint pose a risk).

Lead used to be added to gasoline to help boost its octane and prevent engine knocking. But this has been phased out in most countries because it ruins catalytic converters (an important part of a car's smog-reduction system), and to avoid environmental and health problems.

Lead-acid batteries are the oldest type of rechargeable battery, and are still in common use in cars, boats, and electric vehicles such as golf carts. They are heavier than most other batteries, but can supply high current and are relatively inexpensive.

Lead is also used in products from China. In 2007, concern was raised with consumers when products were recalled; and even today lead can get into consumer products.

Is it dangerous?

Lead compounds are poisonous, as lead binds with other atoms in your body rather than iron and other metals. This leads to weird cell functions that can lead to illness and, if untreated, death. Lead poisoning can be called saturnism, plumbism, or painter's colic.

Even at levels not deadly, lead causes unwelcome changes in behavior, including learning disabilities and loss of impulse control.

References

== Lithium ==

Shows the position of Lithium on the periodic chart.

%element%'s symbol on the Periodic Table

What does it look and feel like?

Lithium floating in oil

Lithium is a very soft silvery metal, and can be cut with a knife just like butter. Lithium tarnishes quickly in the air, and will turn black within seconds. It is the lightest metal. Its density is only 0.53 g/cm^3, about the same as pine wood. Lithium is light enough to float in water. But like all alkali metals, it also reacts violently with water to form lithium hydroxide (a base) and hydrogen gas. So don't expect any lithium bath toys.

How was it discovered?

Lithium was discovered in 1817 by Johann August Arfwedson whilst studying petalite discovered in a Swedish iron mine.

Where did its name come from?

Did You Know?

• Lithium is one of the few elements that was synthesized by the Big Bang, at the start of the universe.

The name "lithium" comes from the Greek name lithos which means "stone."

Where is it found?

It is found in mineral springs and is found in most igneous rocks.

What are its uses?

Lithium is used to transfer heat from one object to the next. Some things lithium is used in are glasses, organic compounds, and ceramics. Because it is such a good conductor of electricity, it is used in batteries as well. Lithium salts are also used in medicine as a mood-stabilizing medication for patients with bipolar disorder.

Is it dangerous?

Lithium is toxic except in small doses, mostly because it is so reactive. It is dangerous and can cause an allergic reaction when near skin.
== Mercury ==

Shows the position of Mercury on the periodic chart.

Mercury's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Some mercury in a jar.

Mercury is a silvery metal that is liquid at room temperature. It is very dense, which means that it is very heavy even if you don't have very much of it. One tablespoon of mercury would weigh almost 8 ounces (230 grams) — this is heavy enough for metal objects like coins to float in it!

How was it discovered?

Mercury has been known since ancient times. It was known to the Chinese and Hindus. In fact, a Chinese emperor's tomb had a map of China inside, with the seas made of mercury.

Where did its name come from?

Mercury is named after the Roman god Mercurius. We call him Mercury. It is also called quicksilver because of its appearance. Its Latin name is hydgargyrum, which means "liquid silver".

Did You Know?

• Mercury is the only metal that is liquid at room temperature.
• Half of the world's mercury comes from Spain and Italy.
• Mercury has been found in 3,500 year-old Egyptian tombs.
• Mercury destroys almost any other metal, one reason it's not safe onboard an airplane.

Where is it found?

Mercury is very rare, and is mostly found in some rocks like cinnabar (mercuric sulfide, or HgS.) Most of the mercury reserves on Earth have been mined out so that there isn't much mercury left in them.

What are its uses?

A compact fluorescent bulb contains very small amounts of mercury.

Mercury used to be used in thermometers, but mercury-in-glass thermometers are less common these days.

Mercury is also a major ingredient in amalgam fillings for teeth, typically being half of the material, but these are also less common nowadays.

Mercury is used in compact fluorescent bulbs, street lamps, and advertising signs.

The antiseptic mercuric chloride (Hg₂Cl₂), also known as calomel, is used to kill bacteria. Mercuric sulfide (HgS) is used to make vermilion, a red pigment used in paint. Mercuric batteries are made from mercuric oxide (HgO).

Mercury is still used today by gold miners in South America to separate gold from the powdered ore.

Is it dangerous?

Yes. Mercury is very poisonous. Mercury can enter the body through the respiratory tract (as mercury vapor), digestive system or skin. Mercury builds up in the body which eventually leads to illness or death. Mercury poisoning is called mercurialism. Mercury pollution is a problem because it can get into our food, especially seafood, where it forms toxic dimethyl mercury ((CH₃)₂Hg), which poisons anyone who eats seafood contaminated with it. Fish have a lot of mercury in them because they are high on the food chain, and therefore accumulate mercury from all the smaller fishes they eat. That is why eating too much salmon or tuna can be bad for you.

Mercury does not poison right away, but rather it is toxic, and can cause brain damage.

References

== Magnesium ==

Shows the position of Magnesium on the periodic chart.

Magnesium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

A small piece of magnesium.

Magnesium as a metal is silver-white and lightweight. It is pictured here in a stick, but it also comes in powder form. Surprisingly, it can be bought by the average person, usually for medical reasons. Magnesium is also softer than other metals. If you've ever tried to bend a metal spoon (these are usually made of steel, a very strong metal) you probably couldn't. If that same spoon was made of magnesium, you could easily bend it. It doesn't smell like anything on its own, because metals don't really smell like anything. The smell you think of when you think of metals is because of a reaction between the oil on your hands and the metal.

Magnesium in crystalized form.

How was it discovered?

A French-Scottish physician and chemist named Joseph Black discovered magnesium in 1755 in England. Sir Humphry Davy electrolytically isolated pure magnesium metal in 1808.

Where did its name come from?

Magnesium gets its name from the Greek word for a district in the Greek region of Thessaly called Magnesia.

Did You Know?

• Magnesium is the eighth most abundant element.
• 1.3 kilograms of magnesium can be found in every cubic kilometer of sea water.
• Magnesium is used in marine flares and fireworks to produce a brilliant white light.

Where is it found?

Magnesium as a pure metal is not found in nature, because it is very reactive and doesn't like to exist on its own, but it is very common as an ion in various compounds as it is more stable in this form.

Magnesium is very common on earth and in seawater.

Magnesium can be found in green vegetables, especially darker green ones. This is because chlorophyll, the green pigment in plants, contains magnesium.

What are its uses?

Magnesium is necessary for all living cells. It is used to help our body make molecules like DNA. Plants also use magnesium as a part of chlorophyll for photosynthesis.

Magnesium burns very bright white. In the old days, magnesium could be used as a light source and was used to create the flash for cameras. Now, it is used in some fireworks. It is also used to make incendiary bombs.

Since magnesium is one-third lighter than aluminum, it is combined with other metals to make missiles and aircraft. Many automakers use magnesium alloys in their vehicles. Some car batteries use magnesium.

Magnesium oxide (MgO), also called magnesia, is used in some stomach antacids. Magnesium is also used to make epsom salts, which is used to treat minor skin abrasions.

Magnesium is also used for construction. It is known as one of the lightest metals that can be used for construction.

Is it dangerous?

Magnesium is highly flammable, and the bright light it gives off can damage the eyes. Never place it in fire, as it burns at an EXTREMELY high temperature, and never throw it into an acid which might cause the release of flammable hydrogen gas. Keep it away from children.

References

== Manganese ==

Shows the position of Manganese on the periodic chart.

Manganese' symbol on the Periodic Table

A sample of manganese.

What does it look, feel, taste, or smell like?

Manganese is a light gray metal resembling iron. It is a hard metal and is very brittle.

How was it discovered?

Manganese dioxide was used to color cave paintings more than twenty thousand years ago. It has been used in glass-making for a few thousand years. More recently, alchemists experimented with it. In the 1700s, chemists were aware there was an element in it that they hadn't yet identified. The element manganese was first isolated in 1774 by Johan Gahn, a Swedish chemist.

Where did its name come from?

Did You Know?

• Steel made with 12% manganese was used for the Brodie Helmet worn by British soldiers in World War I.
• Managese dioxide was used to color cave paintings more than twenty thousand years ago.
• Yet another interesting fact.

In ancient times, a black mineral was found in in what is now modern Greece, in an area called Magnesia. The ore was used to make glass clearer. In the 16th century, a doctor, Michele Mercati, called the ore Manganesa and later the metal isolated from it became known as manganese.

Where is it found?

Manganese is found all over the world..

What are its uses?

It is in steel, batteries, and ceramics. It was found in cave paintings in France. Its atomic number is 25. Maganese-53 is radioactive, with a half-life of 3.74 years (the time it takes for half of the radioactive material to be gone). It has 25 protons and 30 neutrons.

Is it dangerous?

The human body needs a bit of manganese, but in such tiny amounts that it's almost impossible for anyone to have too little of it. Like most metals, it can be toxic in large amounts.

References

== Neodymium ==

Shows the position of Neodymium on the periodic chart.

Neodymium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

5 grams Ultrapure Neodymium under Argon

It has a color of yield pink and nitrate salts create from nitric acid.

Where did its name come from?

The name “Neodymium” came from the Greek words “neos” and “didymos” which mean new and twin. Combined together is “new twin”.

Where is it found?

In 1855, the element Neodymium was found by Carl F. Auer von Welsbach, an Austrian chemist.

What are its uses?

Neodymium magnet

Neodymium have several important uses. It can be a kind of laser called neodymium yttrium aluminum garnet laser (Nd:YAG). This laser is used for treating bronchial (part of the lungs) cancer, eye disorders. Another use is make very strong magnets, the strongest magnet Neodymium-iron-boron (NIB) is also made from the element Neodymium. These magnets are used in audio speakers.

Did You Know?

• Neodymium is in group 6 in the Rare-Earth elements part and it have 60 protons, 84 neutrons.
• The melting point of Neodymium is 1024 C and the boiling point is 3074 C.

Neodymium is also for light devices. There is also a company that made a lightbulb called “Enrich” bulb. The company put small amount of Neodymium into glass of their bulb to produce yellowish and greenish colors. The light from Enrich bulb is highly bright white light.

The last use of Neodymium is coloring glass. As I mentioned above, a small amount of Neodymium added to the lightbulb will gives it a greenish color, this can also be applied for glass. Some of Tiffany lamps use Neodymium in the lampshades.

Is it dangerous?

It's dangerous when you hold a big one but if it's small you can hold it with your hand
== Neon ==

Shows the position of Neon on the periodic chart.

Neon's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Neon is a colorless, odorless gas at room temperature.

How was it discovered?

It was discovered by Scottish chemist William Ramsay and English chemist Morris Travers in 1898 in London, England.

Where did its name come from?

Neon gets its name from Greek neos, meaning "new".

Did You Know?

• Neon is used in lighting.
• Neon, when in a plasma state, emits a reddish-orange glow.
• Air is the only source of Neon.

Where is it found?

Neon is a gas that is common in the universe but rare on Earth itself. Neon can be found in the earth's atmosphere, in small amounts. It is the fourth most common element in the atmosphere behind nitrogen, oxygen and argon. Because it is a noble, inert gas, it forms no compounds.

What are its uses?

Neon is used in lighting and some lasers. Below is an example of the characteristic reddish-orange glow emitted by Neon plasma.

A lighted sign containing neon

Is it dangerous?

No. Neon is an inert gas. It is odorless, and has no effects. Neon lights do get hot, though, so you can burn yourself by touching them. Also, breathing in pure neon gas can cause suffocation because it contains no oxygen, which is what your cells need to produce energy.

References

== Neptunium ==

Shows the position of Neptunium on the periodic table.

Neptunium's symbol on the Periodic Table

Neptunium is an element with atomic number 93, standing between plutonium and uranium. It also has the symbol "Np" and an atomic weight of 237u.

What does it look, feel, taste, or smell like?

Neptunium is a hard, ductile and radioactive metal. It has a silver colour which tarnishes when it is exposed to air.

Where did its name come from

Neptunium was named after the planet Neptune.

How was it discovered?

Neptunium was first discovered in 1934 by Italian scientist Enrico Fermi. Fermi found you could create neptunium by bombarding uranium with neutrons which would cause the uranium to be unstable and then split into two elements, one is neptunium.

What are it uses?

Neptunium is fissionable, which means it can be used to create weapons such as nuclear bombs. However, neptunium still requires more studies to maximize it uses.

Is it dangerous?

Neptunium is an incredibly dangerous actinide metal to contact due to its radioactivity.

Facts

Density: 11.48 ounces per cubic inch (19.86 grams per cubic cm).
Phase at room temperature: solid.
Melting point: 1,191 degrees Fahrenheit (644 degrees Celsius).
Boiling point: 7,052 F (3,900 C).
Most common isotope: Np-237.

== Nickel ==

Shows the position of Nickel on the periodic chart.

Nickel's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

This is a hunk of nickel.

Nickel is a silvery white metal.

How was it discovered?

Nickel was discovered in 1751 in Stockholm, Sweden by a Swedish scientist named Axel Fredric Cronstedt.

Where did its name come from?

Nickel was named after a mischievous German sprite, Nickel, after miners blamed him for being unable to extract any copper from what they thought was copper ore, but which actually contained nickel.

Did You Know?

• US nickel coins are only 25% nickel; the other 75% is copper.
• Some hooks have a layer of nickel so that they oxidize in a slower rate.

Where is it found?

The largest producers of Nickel are the Philippines, Indonesia, Russia, Australia, and Canada (in that order). It was recently discovered in Nigeria (Dangoma).

What are its uses?

Nickel is used to make nickels. This one is from World War Two

Nickel is found in many coins including, of course, nickels.

Is it dangerous?

Nickel compounds are classified as human carcinogens. Nickel can cause allergic reactions from skin contact. This is sometimes a problem with earrings for pierced ears, but many earrings are now made without nickel for this reason.

References

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== Nitrogen ==

Shows the position of Nitrogen on the periodic chart.

Nitrogen's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Nitrogen is a colorless, odorless, and tasteless gas.

How was it discovered?

Daniel Rutherford, a Scottish physicist, discovered Nitrogen in 1772.

Did You Know?

• Nitrogen is the most common element in the atmosphere, making up nearly 80% of it. (The rest is mainly oxygen and argon.)
• Nitrogen is required for all life on Earth, because DNA, RNA, and proteins all contain nitrogen.

Where did its name come from?

Nitrogen's name comes from nitrogenium a combination of words of Latin and Greek that means "native soda forming".

Where is it found?

Liquid Nitrogen can be used to make Ice Cream quickly

Liquid Nitrogen Ice Cream when it is finished

Nitrogen is the world's fifth abundant element, making up 78% of the Earth's atmosphere. Nitrogen is found primarily in the atmosphere and in living things. The nitrogen cycle is the name of the pathway that describes the passage of nitrogen and nitrogen-containing compounds as they are recycled through molecules in earth's atmosphere, soil, plants and animals, and finally back into the atmosphere.

What are its uses?

Nitrogen is required by all living things to make up molecules like proteins and DNA.

Nitrogen is in fertilizers and helps plants grow.

"Laughing gas" contains nitrous oxide (N₂O) and is used as an anaesthetic.

Is it dangerous?

Nitrogen is not dangerous in most circumstances. Pure nitrogen cannot be breathed; people and other animals need oxygen. Liquid nitrogen is very cold, so it can cause frostbite very rapidly. Some compounds of nitrogen, like the strong acid nitric acid and explosives (among them nitroglycerin, which is the active ingredient in dynamite) are very dangerous.

The bends

The bends is a medical condition that is caused by rapid decompression of the body. As a diver dives deep underwater, nitrogen becomes dissolved in the bloodstream due to the pressure of the water. However, if the diver moves to the surface too quickly, there will be a rapid decrease in pressure. This will cause the nitrogen in the bloodstream to form bubbles in the bloodstream, which is potentially deadly.

References

== Oganesson ==

Shows the position of Oganesson on the periodic chart.

This element's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Oganesson doesn't exist in nature on Earth. Three atoms have been made so far by scientists in a laboratory. This isn't enough to see with the naked eye or even an optical microscope so we don't know what it looks like. What they do know is that it is very dangerous and radioactive, and that it is probably a gas at room temperature.

How was it discovered?

Oganesson was discovered in 2006 by the Joint Institute for Nuclear Research in Russia and Lawrence Livermore National Laboratory in the United States, when they fused together Californium and Calcium, creating an element with an atomic number of 118 and an atomic weight of 294. Because it is so difficult to create Oganesson, the researchers had to shoot 25 million million million Calcium atoms at the Californium target before it was produced.

Where did its name come from?

The element was named after Dr. Yuri Oganessian, who is a Russian researcher at the Joint Institute for Nuclear Research, who has been at the facility for over fifty years. He lead the team that helped discover Flerovium, as well as the team that discovered Oganesson, so it was named after him.

He is one of only two people to have an element named after him while he was still alive, the other being Seaborgium, element number 106, after Glenn Seaborg.

Did You Know?

• Oganesson is so unstable that due to radioactive decay half of it will have changed into a different element in less than ¹/₁₀₀₀ of a second.
• Oganesson is sometimes called Ekaradon, because it is below radon in the periodic table.

Where is it found?

Oganesson doesn't occur naturally. If it did, it would be extremely radioactive and so quickly decay almost as soon as it was produced. Instead, it can only be found in laboratories.

What are its uses?

Because Oganesson is so radioactive and extremely difficult to produce, it has no practical uses. The only use it can have is for scientists to research it and improve their theories about atoms and elements.
== Oxygen ==

Shows the position of Oxygen on the periodic chart.

Oxygen's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Oxygen comes in two common forms. They are diatomic oxygen (O₂) and ozone (O₃). Although larger molecules such as O₄ and O₈ can occur under very rare conditions. O₂ is a colorless gas in most conditions, but when it is liquid it becomes blue. O₃ is a blue, toxic gas with a sharp odor.

How was it discovered?

In 1772, Carl Wilhelm Scheele discovered that heating mineral oxides generated a gas that supported combustion (burning) better than air. He was able to collect a pure form of this gas for his experiments, but waited several years to publish his results.

In the meantime, in 1774, Joseph Priestley independently performed similar experiments to generate and collect oxygen gas. Like Scheele, he demonstrated oxygen's ability to support combustion better than air. In addition, he showed oxygen was able to support life in mice up to four times as long as in air. He promptly published his results and is generally credited as the discoverer of oxygen.

Where did its name come from?

Oxygen comes from Greek and means "acid forming". When oxygen was named, scientists thought all acids contain oxygen. Now we know that's not true, although lots of them do. For example, acetic acid, CH₃COOH, which is the acid in vinegar and sulfuric acid, H₂SO₄, do contain oxygen, but hydrochloric acid, HCl, does not.

Did You Know?

• Oxygen is the most common element in the Earth's crust.
• Most of the oxygen in our atmosphere comes from photosynthesis in plants or biosynthesis in bacteria.
• Oxygen is the third most common element in the universe.
• Oxygen is responsible for 61% of your body weight.

Where is it found?

Oxygen is found all over the Earth, in the crust and in the atmosphere. Oxygen is also found in the water that covers most of the earth's surface.

What are its uses?

Scuba divers use tanks filled with a mixture of oxygen and nitrogen to breathe under water. Water itself is made from oxygen and hydrogen atoms.

Without oxygen, life as we know it would not exist. There are only a few microbes known that do not require oxygen to live. Every other life form including tiny bacteria, fungus, trees, animals and people needs oxygen. Oxygen is crucial to our bodies — we breathe oxygen: we need oxygen from the air to survive.

Ozone in the atmosphere helps shield the Earth from harmful UV rays given off by the sun.

Oxygen is used along with another gas called acetylene to power metal welding or cutting torches. Rockets carry oxygen in tanks to mix with fuel. The combustion of the fuel and the oxygen is what propels the rocket.

Scuba divers carry tanks of oxygen mixed with nitrogen that allow them to breathe under water.

It is also used in respirators in hospitals for people who can't get enough oxygen themselves (for instance, if they can't breathe on their own.)

Is it dangerous?

O₂ can actually be toxic, even though we rely on it to survive. This is only true at very high concentrations of oxygen.

Ozone can be toxic because it oxidizes things even more easily than O₂.

Oxygen can also help the spread of fire, so it can be dangerous for that reason.

Oxygen is very reactive, and, as a result, can combine with other elements very easily. Some of those compounds are more dangerous than the element. Oxides of nitrogen and sulfur are very dangerous.

Liquid oxygen is dangerous because of its cold temperature alone. Paradoxically it is even more of a fire hazard than oxygen at room temperature because it is more dense than not-so-cold oxygen. Objects that can burn that are placed in liquid oxygen absorb oxygen and become even more violently flammable.

References

== Phosphorus ==

Shows the position of Phosphorus on the periodic chart.

Phosphorus's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

White phosphorus, red phosphorus, purple phosphorus, and black phosphorus

Phosphorus is white, purple, red, or black in color. When phosphorus is combined with certain other elements, it glows in the dark. Phosphorus can smell like garlic. It is not usually found free in nature.

How was it discovered?

Phosphorus was discovered by Hennig Brand in 1669 through experiments that involved boiling down and distilling the residue from urine.

Where did its name come from?

The name "phosphorus" comes from the combination of the Greek words "phos" (light) and "phoros" (bearer).

Did You Know?

• Plants need a small amount of phosphorus to live.
• One type of phosphorus can be changed into another by increasing the temperature or the pressure.

Where is it found?

Elemental phosphorus comes in four forms: white phosphorus, red phosphorus, purple phosphorus, and black phosphorus. White phosphorus is very reactive and will spontaneously combust (burst into flames) when exposed to warm air. Therefore it is usually stored under water. The other forms are relatively nonreactive. One compound of phosphorus, calcium phosphate (${\ce {Ca3(PO4)2}}$), is a major component of bones. Another, ATP, is used by cells to produce energy.

What are its uses?

Phosphorus is used in fertilizers and detergents. Phosphoric acid (H₃PO₄) is used to make soft drinks. Some phosphorus compounds are used to make light bulbs and television sets. Drinking water with phosphorus or taking phosphorus pills became fashionable and was thought to increase brain activity and make you smarter in the mid-1800s when phosphorus was discovered in the brain. In an ironic twist, phosphorus was used by the Allies in World War II to make their bombs glow bright during nighttime raids over Germany, the country of its initial discovery almost 300 years earlier. Phosphorus is also used to make nerve gas and inside glow sticks.

Is it dangerous?

White phosphorus is very toxic and is very damaging to human tissues, especially bones and cartilage. White phosphorus will spontaneously combust (burn) if exposed to air warmer than 35 degrees Celsius. Red, purple, and black phosphorus are relatively safe to handle.

Atom Information

Diagram of a Phosphorus Atom

The phosphorus atom (pictured right) shows a view of it very, very, zoomed in. At this level we can't even see light but if we magically could - this is more or less what we would see. In the centre is the nucleus (purple + red "subatomic particles") and around it are 3 electron "shells", the nucleus is made up of protons (red) and neutrons (purple). The protons have a little "+" sign on them because they carry positive charge, neutrons have no charge and electrons orbiting around the outside (blue) have a "-" sign because they have negative charge.

Ext: Electron Shells

On the 3 shells, the inner, middle, and outer, you can see varying amounts of electrons on the rings. On the inner ring, you can see two electrons.

References

== Platinum ==

Shows the position of Platinum on the periodic chart.

Platinum's symbol on the Periodic Table

What does it look like?

A few native platinum nuggets

Platinum is a heavy metal that is grayish-white.

It has a melting point of one thousand seven hundred sixty-eight degrees Celsius. This is hotter that a Bunsen burner flame. Heating platinum to this temperature makes it glow a reddish-orange color. Heating it up even more, to three thousand eight hundred twenty-five degrees Celsius, will turn it into a glowing orange gas.

How was it discovered?

It was first discovered by South Americans and used by pre-Columbian Indians. It was taken to Europe in the 1750s.

Where did its name come from?

Did You Know?

• Platinum, even though it is a metal, can be scratched by minerals such as fluorite
• Platinum is a valuable metal, costing just over £1000 per ounce

Its name came from the Spanish word platina (meaning "little silver").

Where is it found?

Platinum is found in South America and Russia. It is obtained as a by-product of nickel and copper mining and processing.

What are its uses?

Platinum is used in jewelry, laboratory equipment, electical contacts, and dentistry. It is also used in the catalytic converter inside cars.

Is it dangerous?

Yes. According to the Centers for Disease Control and Prevention, short-term exposure to platinum salts "may cause irritation of the eyes, nose, and throat" and long-term exposure "may cause both respiratory and skin allergies."

References

== Plutonium ==

This is the position of plutonium on the periodic table.

Plutonium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Plutonium is silver when pure and turns a yellowish color when it oxidizes. A large piece of Plutonium is warm to the touch, and even larger pieces produce enough heat to boil water.

"Fat Man", the second and last nuclear weapon used in warfare, as seen from an airplane above Nagasaki. It used plutonium.

A disk of pure plutonium.

Plutonium (pronounced /pluːˈtoʊniəm/) is a radioactive, metallic and toxic chemical element. It has the symbol Pu and the atomic number 94. It is a fissile element used in most modern nuclear weapons. The most significant isotope of plutonium is ²³⁹Pu, with a half-life of 24,100 years. It can be made from natural uranium and is the most useful fissile isotope of plutonium. The most stable isotope is ²⁴⁴Pu, with a half-life of about 80 million years, long enough to be found in extremely small quantities in nature, making ²⁴⁴Pu the nucleon-richest atom that naturally occurs in the Earth's crust, albeit in small traces.

How was it discovered?

Plutonium was first made by Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan and Arthur C. Wahl at the University of California, Berkley in 1940. It is, therefore, an artificial element (although it IS found in extremely small quantities in nature.) It was created for use in the atomic bomb.

Where did its name come from?

Plutonium was named for the planet Pluto. There is an interesting story behind its abbreviation, though. It became Pu instead of Pl because the discoverers, knowing it to be a dangerous element, chose Pu. Have you ever heard the exclamation "P.U.!" used? Well, now you can make a connection to the world of atoms and molecules.

Did You Know?

• One kilogram of plutonium produces 22 million kilowatt hours of heat energy.
• Plutonium has been used to power space probes and heart pacemakers.
• It was used aboard Apollo 14 to power seismic devices.

A piece of plutonium glowing under its own light.

Where is it found?

Plutonium is usually manufactured artificially in special reactors designed and built especially for this task. Trace amounts of plutonium have also been found naturally inside some uranium ores. It's virtually nonexistent, however, in the soil.

What are its uses?

The most well known use of plutonium is in the building of nuclear weapons and power plants, using its isotope 239. It is one of the key materials that cause the nuclear explosion. Less well known, however, it has been used in many instances to build long-lasting batteries for things like space probes/satellites and heart pacemakers. The heart-pacemaker use of plutonium uses the isotope 238, just one neutron away from the deadly isotope 239. If it (naturally or artificially) gained just one neutron, the heart pacemaker would probably kill you if you used it. The use of plutonium as a power source for pacemakers has been stopped in more recent years, due to this.

Is it dangerous?

Raw plutonium is both radioactive and toxic. If it comes in contact with a person, it is likely to cause an increased chance of cancer in later years of life. If ingested or inhaled it can be toxic. When used to build weapons, plutonium is extremely dangerous. It is used in the two most powerful and deadliest weapons of all time, the atomic and hydrogen bombs.

References

== Polonium ==

Shows the position of Polonium on the periodic chart.

Polonium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Polonium is a silvery metal at room temperature. It feels much like its neighbor, lead. You would not want to taste it as it is deadly poison.

How was it discovered?

Polonium was discovered by Marie and Pierre Curie in 1898. They isolated it from pitchblende, which also contains uranium.

Where did its name come from?

The name "polonium" comes from Poland, where Marie Curie was born. It is also referred to as Radium F.

Did You Know?

• Polonium is so radioactive that it spontaneously heats up and vaporises, even at room temperature.

Where is it found?

Polonium is very rare and only occurs as an impurity in some uranium ores.

What are its uses?

Polonium doesn't have much use because it's so radioactive. Because it produces so much heat from its radioactivity, it's used in some generators which use that heat to produce electricity.

Is it dangerous?

Polonium is toxic and radioactive. This radioactivity is very dangerous. Because polonium is so radioactive, it heats up quickly and can cause burns.
== Potassium ==

Shows the position of Potassium on the periodic chart.

Potassium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Potassium feldspar

Potassium is metallic and silvery white. It is soft, waxy and can easily be cut with a knife. Potassium has a lilac colored flame and burns when in contact with water. It reacts with oxygen to form potassium superoxide (${\ce {KO2}}$) and with water to form potassium hydroxide (${\ce {KOH}}$), hydrogen gas and heat. Enough heat is produced to ignite the hydrogen gas.

How was it discovered?

It was discovered in 1807 when Sir Humphrey Davy extracted it from potassium hydroxide (or caustic potash, KOH,) a compound used in cooking.

Where did its name come from?

The name "potassium" comes from the Dutch word Potasch. Potassium was discovered in 1807 in England by Sir Humphry Davy.

Potassium's chemical symbol, K, comes from the Arabic word القلية (al-qalya), meaning potash, formed into the Latin word "kalium", most likely because it is an alkali metal.

Did You Know?

Potassium is important for your nerves and muscles.

Where is it found?

Potassium makes up nearly 3% of the Earth's crust and is the seventh most abundant element on the planet. Potassium is rarely found free in nature as it is a very reactive element. Instead, potassium is usually found in minerals such as sylvite, carnallite, langbeinite, and polyhalite. These minerals are usually found in ancient lake and sea beds. Another important source of potassium, caustic potash, is mined in Germany as well as New Mexico, California and Utah in the United States.

What are its uses?

Plants need potassium to grow. Potassium can be found it most soils, usually in the form of potassium chloride (KCl) or potassium nitrate (KNO₃). In addition, potassium chloride is a salt substitute and aids in the production of other chemicals. Potassium nitrate, also known as saltpeter or niter, is also used to make the heads of matches and pyrotechnics (it is the major component of gunpowder.) Potassium hydroxide (KOH) can be found in soaps, detergents and drain cleaners. Potassium carbonate (KHCO₃), or pearl ash, is a byproduct of ammonia that can be found in certain types of soap and glass. Potassium is also found in bananas.

Is it dangerous?

Pure potassium, as a metal, will light on fire if it touches water. However, potassium is a required mineral in the body as an ion — an electric atom. One of its uses inside the body is in the nerves. Nerves, and neurons in the brain, carry electricity; the potassium ion, along with the sodium ion, are important to this.

Potassium hydroxide and its solutions should never be touched in any way, as they are EXTREMELY POISONOUS AND CORROSIVE!!!!!!!!!!!!!!!!!!!.

References

== Promethium ==

Shows the position of Promethium on the periodic chart.

Promethium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

It is likely silvery coloured and somewhat hard. Not many people have seen it as it is very rare and radioactive.

How was it discovered?

Scientists had guessed that there an element with atomic number 61 existed many years before it was found. After a number of claims to have found it by different scientists, it was decided that promethium did not occur naturally. In 1945 the Oak Ridge National Laboratory in the United States found Promethium during an investigation of the results of splitting uranium fuel in a nuclear reactor. They were too busy at the time (this was during World War II) to tell anyone about the discovery so it only became widely known in 1947.

Where did its name come from?

The first suggested name was "clintonium", named after the laboratory where it was found, but in the end "prometheum" was suggested after the name of Prometheus, the Titan in Greek mythology who stole fire from Mount Olympus. The spelling was changed to "promethium" to match the style of names of other similar elements.

Where is it found?

Promethium is found in the Earth's crust. It is found in uranium ore because of uranium's decay, but not much promethium exists in the world.

What are its uses?

Promethium is used to make small atomic batteries. Like radium, it is also sometimes used to paint the hands and the numbers on the dial of a watch to make them glow in the dark.

Is it dangerous?

It is dangerous as it is very radioactive. This radioactivity can cause cancer later in life.

References

== Radium ==

Radium element on Periodic table

What does it look, feel, taste, or smell like?

It's a silver - white and it will react with nitrogen on exposure air. The hardness and texture is unknown because it is radioactive so it's impossible for people to find out.

How was it discovered?

It was discovered by Pierre and Marie Curie in 1898.

Where did its name come from?

This word was created by the word “Radius" in Latin word and it means ray, they created this name after they saw the rays glow from the element

Did You Know?

• Density is 5g/ml.
• The radioactive of the radium is really high.
• Because the radium is high radioactive so it's impossible for people to find out.

Where is it found?

Radium was first found in Bohemia in the rich pitchblende ore. Some can also be found in the Carnotite sands of Colorado, although richer supplies exist in regions of Zaire, Africa and the Great Bear Lake region of Canada.

What are its uses?

Radium is used to kill cancer disease or also use for x-ray. But it’s so expensive so people didn't use it too much. The most common way to use radium is to make the clock glow when it’s in dark place when they mix radium with phosphor. And now, they use it to treat some types of cancer.

Is it dangerous?

First, we can find radium in rocks like that and you walk along and you just contact with it for a short time, it's not affect to your health. But if you contact with radium for a long time, it can be harmful to your health. 
== Radon ==

Shows the position of radon on the periodic chart.

Radon's symbol on the Periodic Table

Radon detector

What does it look, feel, taste, or smell like?

Radon is an invisible, odorless gas. You can't see, smell, or taste it.

How was it discovered?

Radon was discovered in 1900 by Friedrich Ernst Dorn. Dorn originally called the gas "radium emanation". The gas was later called "niton", and, in 1923, it became "radon". It was named after the element radium.

Where did its name come from?

Radon was named for radium, another element, which decays (breaks down) into it.

Did You Know?

• Radon is the heaviest noble gas.
• It was originally called radium emanation.
• Radon is the second leading cause of lung cancer (after tobacco smoking.)

Where is it found?

Radon test kit

Radon makes up a small part of the air. It naturally comes up from the ground. It is released from the decay of uranium in rocks and soil. Radon is created when radium in the earth's crust decays.

What are its uses?

It is used to treat some forms of cancer, and is also used in earthquake prediction.

Is it dangerous?

Radon is highly radioactive. Based on studies carried out by the National Academy of Sciences in the United States, radon is the second most common cause of lung cancer, after tobacco smoking. Homes need to be regularly tested for it.

References

• Radon and Cancer: Questions and Answers
• Los Alamos National Laboratory - Radon

== Rubidium ==

Shows the position of Rubidium on the periodic chart.

Rubidium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Rubidium metal

Rubidium is silvery white. It is a soft metal — ductile, meaning it can be drawn out into thin wire without breaking. It has no smell.

How was it discovered?

It was discovered in 1861 by two German chemists, Robert Bunsen and Gustav Kirchhoff, using flame spectroscopy. Flame spectroscopy was a new technique at the time; scientists heat material with a flame and observe the spectrum of light the material emits.

Where did its name come from?

Bunsen and Kirchhoff named this element after the color of the light they observed from it with their spectroscope. The Latin word rubidus means red.

Did You Know?

• Rubidium ignites spontaneously in the air.
• It helps make fireworks purple.
• The name Rubidium comes from the latin term for "deep red," Rubidus

Where is it found?

It occurs naturally in the minerals leucite, pollucite, carnallite, and zinnwaldite, which contain as much as 1% rubidium oxide. Lepidolite contains between 0.3% and 3.5% rubidium, and is the commercial source of the element.

What are its uses?

Rubidium is used in some fireworks, for its color. It is also used for various high-tech devices. It is used in vacuum tubes as a getter, a material that combines with and removes trace gases from inside the tubes, to keep the inside of the tube a vacuum. It is used in lasers and high-precision clocks. It is also used in the manufacture of photocells and in special kinds of glass. Since it is easily ionized, it might be used as a propellant in ion engines on spacecraft.

Is it dangerous?

Rubidium burns when exposed to water, like potassium.

References

== Scandium ==

Shows the position of Scandium on the periodic chart.

Scandium's symbol on the Periodic Table

What does it look, feel, or taste like?

Scandium crystals and cube

Mallet and iron

Scandium is a soft metal with a silvery appearance. It develops a slightly yellowish or pinkish cast when oxidized by air.

How was it discovered?

The element scandium was discovered because an element that was previously unknown was shown in Mendeleev's periodic table. Lars Fredrik Nilson specifically looked for it and found it in 1879.

What are its uses?

It is used in mercury vapor lamps.

Is it dangerous?

Scandium powder burns easily.

• 
  flammable

== Silicon ==

Shows the position of Silicon on the periodic chart.

Silicon's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

A quartz crystal. Quartz is made of Silicon dioxide

Silicon is a dark grey and metallic-looking solid. However, silicon is not a metal (or even a non-metal); it comes under a special category of elements called as metalloids which are those which have some properties of both metals and non-metals (between metals and non-metals).

How was it discovered?

Silicon was first identified by Antoine Lavoisier in 1787. It was then discovered by Jons Jacob Berzelius in Stockholm, Sweden in 1823.

Where did its name come from?

Silicon gets its name from silicis, which is Latin for flint.

Did You Know?

• Silicon is the second-most abundant element in the Earth's crust, behind only oxygen.

Where is it found?

Silicon is present in the sun and meteorites. Silicon makes up one quarter of the earth's crust. It is the second most abundant element on Earth, behind only oxygen. Silicon is not found free in nature, but occurs chiefly as silicon dioxide and as silicates. Sand, quartz, rock crystal, amethyst, agate, flint, jasper, and opal are some of the forms in which the dioxide appears. Granite, feldspar, clay, and mica are some of the silicate minerals.

What are its uses?

A computer chip is etched on a thin wafer of silicon.

Silicon is one of the most useful elements. In the form of sand and clay it is used to make concrete and brick. Silicates are used in making enamels, and pottery. Silica, as sand, is the principal ingredient of glass. Glass can be made into bottles, windows, lenses, and thousands of other objects.

Silicon can be used in transistors, solar cells, microprocessors and other electronic devices. It is an important ingredient in steel. Silicon carbide is used as an abrasive, and is used to coat some sandpapers

Is it dangerous?

No, silicon is not generally dangerous, but miners and stonecutters can develop a serious lung disease known as silicosis if they breathe in too much silicate dust, because the sharp edges of the silicate particles tear the alveoli (parts used to absorb oxygen from the air) and cause damage to the lungs.

References

== Silver ==

Shows the position of Silver on the periodic chart.

Silver's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

A nugget of silver.

Silver is a soft metal that has a brilliant, white luster. Silver is a little harder than gold. Silver looks a bit like granite when it has been mined.

Silver has a sweet and sour taste.

How was it discovered?

Silver has been known since ancient times. Silver was mentioned in the Genesis chapter of the Bible. Man learned how to separate silver from lead in Asia Minor and islands on the Aegean Sea starting in 3,000 B.C.

Where did its name come from?

Silver gets its name from the Anglo-Saxon seolfor. In Latin, silver was called argentum. Have you heard of the country Argentina? Well, the Spanish at first went to Argentina in search of silver, and that is why that country has been named so.

Did You Know?

• Silver conducts electricity better than all other metals.
• Silver is the whitest metal.
• Silver is the best known reflector of visible light.

Where is it found?

Mexico is currently the world's largest producer of silver. Other major silver producing countries include Canada, Peru and the United States.

Silver is found in ores such as argentite, light ruby silver, dark ruby silver and brittle silver.

What are its uses?

Silver has been used in jewelry, tableware, and in silver medals. Silver has been used in coin production for centuries. Silver is also used in some mirrors, but these mirrors must be given a protective coating in order to keep them from tarnishing. High energy batteries are made using a combination of silver and zinc or silver and cadmium.

Silver bromide (AgBr) is used to make film. So is silver nitrate (AgNO₃), which is a light sensitive compound used to make photographic films and papers. Printed circuits are made using silver based paint. Silver chloride can be made transparent and can also be used as a cement for glass.

Silver can be used to conduct electricity and is better at conducting electricity than any other metal.

Silver iodide (AgI) can be used to make clouds produce rain. It is also used in photography.

Is it dangerous?

Pure silver does not have any health risk, but if mixed with other elements can cause cancer. Silver salts are poisonous. If silver compounds are absorbed by the circulatory system, this can cause a condition known as argyria — a graying of skin pigmentation and mucous membranes.

References

== Sodium ==

Shows the position of Sodium on the periodic chart.

Sodium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Pure sodium is a soft and silvery metal. Sodium is prevented from contact with the air and water and kept by immersion in oil, because it tarnishes very quickly when exposed to air. It is so soft that you could cut it with a butter knife.

How was it discovered?

Sodium was isolated by Sir Humphrey Davy in 1807 from sodium hydroxide.

Where did its name come from?

Sodium gets its name from the English soda. In Latin it was called natrium.

Did You Know?

• Sodium is the sixth most abundant element overall.
• Sodium is the most abundant alkali metal, in the first column of the periodic table.
• Sodium ions taste salty in flavor.

Where is it found?

The most common compound of sodium is sodium chloride, better known as salt, which can be found in seawater and in the mineral halite. Sodium is relatively common in stars. Because sodium is highly reactive, it is never found in its pure state in nature.

What are its uses?

This Beaker Contains Table Salt which is made from Sodium and Chlorine

We use sodium every day. Sodium chloride is used to help flavor food in the form of table salt. Sodium is also found in sodium bicarbonate, also called baking soda. Sodium is also used in most soaps and detergents (although some, such as those in shaving cream, use potassium instead.)

Sodium is also required by the body for proper blood, brain cell action, heart activity, and more. It is so important that animals and people are adapted to tasting sodium. Sodium is salty.

Is it dangerous?

Sodium is highly reactive and may ignite on contact with water. It can even cause an explosion. The strong alkali sodium hydroxide — also called lye — is very corrosive and should never be touched, as it can cause severe chemical burns; neither should solutions of it.

References

== Strange Element ==

The mysterious element not listed on any periodic table.

Does not show the position of the neutron in the periodic table of elements. Location in the periodic table: Directly above the noble gas helium. It comes before the hydrogen (atomic number 1) and has the atomic number 0.

How does it look, smell, and taste?

Individual neutrons cannot be seen, smelled or tasted.

Since neutrons do not attract each other, there are no clumps of neutrons on Earth. Therefore, it is not surprising that neutrons are not listed in the periodic table of the elements. But there are stars made of this element.

Fictional representation of a red giant neutron star (NASA)

How was it discovered?

Walther Bothe and Herbert Becker produced the neutron in 1930 and verified it with a measuring instrument, but they didn't realize what they had discovered. It wasn't until two years later that James Chadwick found out what kind of particle it was and called it a neutron. The average lifespan of individual free neutrons is just under 15 minutes.

Where does the name come from?

The neutron was so named because it is electrically neutral. It has the symbol 'n'. As an element, it is also called neutronium.

Where is it found?

Single neutrons are produced in nuclear reactors.

The neutron star closest to us. It is called RX J1856.5-3754.

Astronomers have also captured images of stars made up only of neutrons.

What possible uses are there?

Neutrons are used in radiation therapy. Neutrons play an important role in nuclear fission as well.

Is it dangerous?

Yes! Neutron radiation is the most dangerous type of radioactive radiation.

• 
  Radioactive

== Strontium ==

Shows the position of Strontium on the periodic chart

Strontium's symbol on the Periodic Table

Strontium is the chemical element with symbol Sr and atomic number 38. It reacts with other elements very easily.

Strontium

What does it look, feel, taste, or smell like?

strontium is a soft silver-white yellowish metallic element that is highly chemically reactive.

How was it discovered?

Strontium was found by Adair Crawford in 1790 in a mine near Strontian, Scotland. At that time, scientists thought strontium and barium were the same element.

Where did its name come from?

Strontium is named after the Scottish village of Strontian, where it was discovered in the ores of the lead mines.

Did You Know?

• Strontium has silvery white color, and it turns into yellow when exposed to air
• It is softer than calcium and harder than barium.
• Primary use for strontium was in glass for colour television cathode-ray tubes, where it prevented X-ray emission.

Where is it found?

It is found naturally on Earth and is mined.

What are its uses?

Strontium salts are used in fireworks and flares for a red color. Strontium chloride is an ingredient in toothpaste for sensitive teeth.

Is it dangerous?

It is not dangerous to health. Strontium can't harm humans but if you inhale it while it's in the chemical form, it can be very harmful for you.

References

== Sulfur ==

Shows the position of Sulfur on the periodic chart.

Sulfur's symbol on the Periodic Table

Sulfur is a common non metallic element with the chemical symbol S and atomic number 16.

A sulfur crystal is bright yellow.

What does it look, feel, taste, or smell like?

It is bright yellow and forms large crystals. In its native (pure) form it is both odorless and tasteless, but many substances containing sulfur have a distinct odor. The scent of rotten eggs, burnt matches, and skunks are all caused by sulfurous compounds.

How was it discovered?

Sulfur was discovered early in human history. References in the Bible associated the element with the devil and hell. The Bible refers to it as brimstone.

Where did its name come from?

The word sulfur has old roots. It comes from the ancient Latin word for sulfur, sulpur, which later changed to sulphur, perhaps under the influence of the Arabic word for yellow, sufra.

Where is it found?

Sulfur melts to a bloodred liquid and burns with a faint blue flame which you can see if you look very closely.

In nature, it can be found as the pure element or combined with other elements as different minerals. Sulfur can be found in areas where there are volcanoes. It is also found in meteorites and hot springs. Sulfur is mined from the ground and can be found throughout the world. A compound of sulfur (hydrogen sulfide or H₂S, in which sulfur is combined with hydrogen) is also a common component of oil and natural gas, especially now that most sulfur-free oil and gas has been used up. A large amount of the element is made from H₂S by oil refineries.

Sulfur ready to be loaded on ships.

Did You Know?

• Sulfur burns with a blue flame.
• The name sulfur is also sometimes spelled sulphur.
• Sulfur boils at 832°F and melts at 239°F.
• Although solid sulfur is bright yellow, molten sulfur is blood red.

What are its uses?

Sulfur is used to make matches and gunpowder. It is also used to make fertilizers to help plants grow, and to make sulfur dioxide (SO₂), which is used to keep dried fruit from discoloring. It is an essential element for life.

Is it dangerous?

When mixed together with other elements, like hydrogen or oxygen, it can cause lung scarring and breathing problems. Sulfuric acid is a strong acid that can cause burns on unprotected skin. Hydrogen sulfide, called "stinkdamp" by miners due to its offensive smell, is a very dangerous gas. Sulfur is an important part of gunpowder. Gunpowder is explosive and is very dangerous if handled incorrectly.

References

== Tellurium ==

Shows the position of Tellurium on the periodic chart.

Tellurium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Ultra pure tellurium crystal

Tellurium is a silver-white metalloid. Tellurium compounds generally smell awful. If a human being is exposed to tellurium, even in very small amounts — keeping in mind, tellurium is toxic, so people shouldn't be exposed to it, even in very small amounts — their body metabolizes it so that their breath then smells so horrible that, reportedly, lab workers exposed to tellurium had to be given a leave of absence till it worked out of their system.

Where did its name come from?

The name "tellurium" comes from the Latin word tellus meaning "earth".

Where is it found?

Did You Know?

• Tellurium is chemically related to selenium and sulfur.
• Tellurium was discovered in the 18th century in a gold ore from the mines in Romania.
• Tellurium has two allotropes, crystalline and amorphous.

Is it dangerous?

Yes. Tellurium is mildly toxic, so people should be very careful when handling it.

References

== Thallium ==

Shows the position of Thallium on the periodic chart

Thallium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

It's tasteless, no color, and no smell. It is malleable, limber, silver-colored and glossy. It tarnishes in air to the bluish-gray oxide.

How was it discovered?

English scientific expert William Crookes found Thallium spectroscopically in 1861. Both Crookes and French scientific expert Claude Auguste Lamy separated the component in 1862 indpendently.

Where did its name come from?

It was discovered by flame spectroscopy in 1861. Because Thallium has the colour bright green, scientists decided to give it the name Thallium, which comes from the Greek word θαλλός, 'thallos' , which means “a green shoot or twig”.

Did You Know?

• About 70% of thallium in the world were used for electronics devices
• Thallium is also used for investigate heart disease
• Thallium will produce a green color to a bunsen flame.

What are its uses?

Thallium is very poisonous. It is also used as one ingredient to make rat and insect poison popularly. Since 1972, this use was prohibited in the US for safety concerns. Some other countries conforming to this example in the following years. Thallium salt also have been used in curing people who have ringworm, other skin infections and to decrease the night sweat of tuberculosis patients. This use has been limited, for their restricted therapeutic index, and the evolution of enhanced drugs for these fettles.

Thallium sulfate (also known as the salt of thallium)

Where is it found?

Thallium is a metal found in small amounts in soil.

Is it dangerous?

Thallium compounds contain the element are very toxic because it is colorless, odorless, tasteless so it is very toxic when you contact with skin.

Thallium in periodic table

Thallium is on column 13, row 6.

== Tin ==

Shows the position of Tin on the periodic chart.

Tin's symbol on the Periodic Table

A metal cube of Tin

General: Tin is a chemical element. Tin belongs to the carbon family of elements on the periodic table. The Periodic Pable arranges the chemical elements into rows (periods) and columns (groups). Chemical elements are represented by symbols. The symbol for tin is Sn, an abbreviation for the Latin word stannum.

What does it look, feel, taste, and smell like?

Tin is silvery-white in color. It has a slightly bluish tinge. Since it is a metal, tin can be polished and made shiny. Tin contains clear particles called crystals.

Tin feels cool to the touch. It is flexible and bends easily. It is soft and can be cut with little effort. Tin is ductile, meaning it can be drawn out into fine strands. Tin is malleable, meaning it can be molded into various shapes.  It can be extruded (pulled) into long tubes. It can be hammered or pressed flat by rollers.

Tin has a metallic taste and is odorless.

Other properties.

1.    Solid tin will melt at about 450 degrees Fahrenheit. This is called the melting point.

2.    Tin easily adheres (sticks) to iron, steel, and copper.

3.    When tin is bent or twisted, the crystals inside crush together to make a cracking sound. This is called a “tin cry”.

4.   Tin has two different forms, white and grey. These different forms are called allotropes. The familiar form is white tin (beta). The less familiar form is

gray tin (alpha). Gray Tin is powdery and of little use. Gray tin changes to white tin when the temperature is above 55.76 degrees Fahrenheit.

Is it dangerous?

Exposure to harmful tin compounds can cause eye and skin irritations, dizziness, and sickness. Such compounds are used for making paint, plastic, fungicides, and pesticides. Some tin compounds are toxic (poisonous).

Pure tin is nontoxic and safe to handle. Food packaged in tin-plated containers has small, harmless amounts of dissolved tin. Metallic Tin and fumes from tin refining are not toxic.   

Where does its name come from?

The English word tin comes from the Anglo-Saxon language. The German word for tin is tin-om. The Latin word for tin is stannum, which means alloy (mixture) of silver and lead. The earlier Latin word for tin was plumbum candidum, which means "white lead".

How was it discovered?

How tin was discovered in ancient times is unknown. Some areas of southwest Britain were not covered by ice during the Ice Age. Tin ore was on the surface in regions that were free of ice. In Brittany, France, and the Iberian Peninsula, tin mines date back 4000 years. Tin played a key role in shaping ancient civilizations.  

Where is it found?

There is evidence that the Inca and Aztec people mined tin in South and Central America.

Tin mining took place in the Ore Mountains in Europe about 4500 years ago. These ancient mines were located on the border between modern day Germany and the Czech Republic. There were tin mines in Brittany, Devon, Cornwell, and the Iberian Peninsula around 2000 BC.

Much of the tin used by early Mediterranean peoples likely came from the English Isles of Scilly and the Cornish Peninsula.

Tin mines in Yunnan began around 2700 years ago. They eventually became China’s main source of tin.

Later, tin mining developed in other regions of the world. Including Africa, Australia, and the Americas.

Important areas where tin is mined in modern times include:

1. The SE Asian tin belt (Myanmar, Thailand, Malaysia, Indonesia).

2. The South China tin belt.

3. The Central Andean tin belt (Bolivia and southernmost Peru).

4. The Cornwall tin province in southwestern England.

Tin is found in Alaska and other areas in the United States, but there are no more active tin mines. The United States has not produced tin since 1993. As of 2017, tin has become a “critical strategic metal”. This means it is needed for technology and industry but is in short supply. There are no known alternatives. The United States receives much of its tin supply from South America. Recycling plays an important role in maintaining the tin supply. Several processes have been developed for reclaiming tin from scrap tin or tin-plated articles.

What are its uses? 

Tin and tin compounds are widely used for:

1.    Reducing friction in moving parts of machines, such as bearings.

2.    Making toothpaste, perfume, polymers and dyes, and lithium batteries.

3.    Plating (coating) steel cans used as food containers.

4.    Soldering (joining) 2 pieces of metal together, mainly for electrical and plumbing work.

5. Grey tin is sometimes used in semi-conductor applications.  

6.   Making alloys such as bronze, pewter, and solder. Because pure tin is relatively weak, it must be mixed with other metals to form alloys. The world’s

first alloy was discovered more than 5,000 years ago. People found that mixing tin and copper produced a hard and durable metal. It could be shaped

into blades which would keep a sharp edge.

References

Castillo, D. (2023, August 22). All about solder: The ultimate guide. Fine Power Tools. https://www.finepowertools.com/diy/solder/

James Sword Research. (n.d.). Metal plating process, A complete guide to its types and techniques. [Video]. Metal Plating Process | A Complete Guide To Its Types And Technique. (youtube.com)

Karl, N., Burger, M., and Long, K. (2018). Tin deposits in the United States: U.S. Geological Survey data release, https://doi.org/10.5066/P97JYNJ

Royal Society of Chemistry. (2024). Tin – Element information, properties and uses. Tin - Element information, properties and uses | Periodic Table (rsc.org)

Skills Store. (2020, August 22). Electrolytic Tinplating. [Video]. YouTube.  Electrolytic tin-plating process complete-tinplate-steel.

S. Rose. (n.d.). What is the element tin used for? Retrieved June 15, 2024, from What is the Element Tin Used For? - Lesson For Kids - Video | Study.com.

Surpua, S. (n.d.). Alloys of tin. Alloys of Tin | Metals | Industries | Metallurgy (engineeringenotes.com)

Encyclopedia Britannica. (n.d.). Tin definition, properties, uses, & facts. Revised and updated by A. Tikkanen. Retrieved June 1, 2024, from Tin | Definition, Properties, Uses, & Facts | Britannica.

 

Did You Know?

• Tin was used, with copper, in the first metal alloy made by humans, bronze, about five thousand years ago.

== Titanium ==

Shows the position of Titanium on the periodic chart.

Titanium's symbol on the Periodic Table

What does it look, feel, or smell like?

A titanium crystal bar.

Titanium is a silvery, light, strong metal. It is odorless. Its texture is rough as well as sharp.

How was it discovered?

Titanium was discovered at Creed, Cornwall in England by amateur geologist Reverend William Gregor in 1791, though he first named it menachite. It was discovered later by German chemist Martin Heinrich Klaproth who called it titanium.

Where did its name come from?

Titanium is named for the Titans of Greek mythology.

Did You Know?

• Titanium is one of the few metals that can fuse with bone.
• Titanium is the ninth most abundant element in the Earth's crust.

Where is it found?

Titanium is never found pure in nature; it is always bonded to other elements.

Titanium is also found in asteroids and on rocks from the moon.

What are its uses?

Because titanium is a light and strong metal, it has a lot of uses. It is used in aircraft, ships, racing bikes, and spacecraft. It can also be found in some computers, golf clubs, and tennis rackets. The compound titanium dioxide is colored bright white, so it used very often in paint.

Is it dangerous?

Titanium is harmless as a metal. However, if titanium is made into powder, or blowed with pure nitrogen gas, it can burn and/or explode.

References

== Tungsten ==

Shows the position of Tungsten on the periodic chart.

Tungsten's symbol on the Periodic Table

What does it look, feel, or taste like?

Tungsten crystals and cube

Tungsten powder in a vial.

Tungsten is a heavy metal that can be from grey to white. Tungsten in its pure form is soft enough to cut with a hacksaw. Tungsten carbide is extremely hard and it is very difficult to cut.

How was it discovered?

In 1783, two Spanish chemists, the de Elhujar brothers, were the first to isolate pure tungsten metal. Tungsten was originally found in the mineral wolframite. "Wolframite" means "the devourer of tin."

Where did its name come from?

Tungsten gets its name from the Swedish word tung sten which means "heavy stone." The "W" in its symbol stands for wolfram, tungsten's German name.

Did You Know?

• Tungsten has the highest melting point of all metals at 3422 °C.

Where is Tungsten found?

Tungsten is found in certain minerals including wolframite ((Fe, Mn)WO₄) and scheelite (CaWO₄). Most of the world's tungsten, about 75%, comes from China. Other major deposits of tungsten can be found in California, Colorado, South Korea, Bolivia, Russia and Portugal.

What are its uses?

An incandescent light bulb and its glowing filament. This filament contains tungsten.

Tungsten is used in incandescent light bulb filaments as the source of light (although, since they are very inefficient, they are less commonly seen nowadays). It is also used in fluorescent light bulbs, television tubes, and x-ray production.

Tungsten is combined with carbon to make tungsten carbide (WC) which is used to make the tips of drill bits, high-speed cutting instruments and mining machinery.

Is it dangerous?

When electric current is passing through it, tungsten can get very hot and could cause a burn.

References

== Uranium ==

Shows the position of Uranium on the periodic chart.

Uranium's symbol on the Periodic Table

What does it look, feel, taste, or smell like?

Uranium ore

Uranium was used in the "Little Boy": the first nuclear bomb used in warfare

Uranium is silvery-white and metallic. Uranium can appear to be slightly blue.

How was it discovered?

Uranium was discovered in 1789 by Martin Klaproth, a German chemist. Klaproth found uranium while he was analyzing samples of pitchblende, a variety of the mineral uranite, from the Joachimsal silver mines in the Kingdom of Bohemia (now located in the present-day Czech Republic). It was discovered to be radioactive by Henri Becquerel in 1896, and until the discovery that thorium was radioactive two years later, in 1898, it was thought to be the only radioactive element.

Where did its name come from?

Uranium is named after the planet Uranus, which had been discovered some years before, in 1781, by William Herschel.

Did You Know?

• Uranium is the highest-numbered element, with a number of 92, to be found naturally in significant quantities on Earth.
• One ton of natural uranium can create over 40 million kilowatt hours of electricity. This is the same amount of energy that would be created by burning 16,000 tons of coal or the contents of 80,000 barrels of oil.
• Native Americans living on the Colorado Plateau used the uranium-bearing mineral carnotite to make bright yellow war paint.

Where is it found?

Uranium is found worldwide in soil and rocks. Australia has the largest known reserves, while the most has been mined in recent years from Kazakhstan, which produced about 23,400 tonnes in 2017.

What are its uses?

Uranium is commonly used in nuclear reactors to make electricity, as well as in nuclear weapons.

Uranium is also used to test the age of very old rocks.

Uranium was used to color paints and glazes, although such use is rare today.

Uranium can also be used to color glass yellow; such uranium glass, or "vaseline glass," glows green under ultraviolet light (also known as a black light.)

Because it is so heavy, uranium is used in armor-piercing artillery bullets.

Is it dangerous?

Pure uranium can burst into flames.

Compounds with uranium in them are toxic.

Uranium is radioactive, and can lead to cancer.

References

== Vanadium ==

Shows the position of vanadium on the periodic chart.

Vanadium's symbol on the Periodic Table

Vanadium

What does it look like?

Vanadium is a shiny, light grey, ductile, metallic-looking solid and strong blue-gray metal at room temperature. Its melting point is about 1,900°C. Its boiling point is about 3,000°C

How was it discovered?

At first, Vanadium was discovered by Del Rio in 1801 but he thought that he had made some mistakes because of the French chemists. They said that Vanadium was similar to the chromium. In 1830, Vanadium was rediscovered by the Swedish chemist Nil Gabriel Sefström at Stockholm.

Where did its name come from?

It was named for the Scandinavian goddess, Vanadis.

Did You Know?

• A higher amount of vanadium can be found in oceanic animals than those living on land.
• Firstly, it was introduced as “rionium" but this name was rejected.
• Most of the vanadium in the world is mined in three countries: South Africa, China, and Russia.

What are its uses?

Vanadium is used in most alloys (the mixture of the metals), especially in making metals that don't rust. It is also used to produce a superconductive magnet.

Is it dangerous?

Vanadium can be toxic but Its effects are not very serious. It can harm the lungs if being taken in a large amount. However, if you work with Vanadium everyday, it could be serious.

== Zinc ==

Shows the position of Zinc on the periodic chart.

Zinc's symbol on the Periodic Table

What does it look, feel, taste or smell like?

Zinc is a hard solid that is bluish in color. It has no smell.

How was it discovered?

Zinc was known to the ancients, but it wasn't until 1746 that zinc was isolated by Andreas Marggraf. Marggraf showed people that zinc could be isolated by reducing calamine with charcoal.

Centuries before the metallic form of zinc was discovered, zinc ores were used for making brass and zinc compounds. An alloy containing 87% zinc has been found in prehistoric ruins in Transylvania. Zinc ores were used for healing wounds and sore eyes. It is estimated that during the rule of Augustus (20 BC to 14 AD), the Romans were the first people to make brass. In the 13th century explorer Marco Polo was cited as describing the production of zinc oxide in Persia. India recognized zinc as a new metal by 1374; at the time, it was the eighth metal known to man. Zinc oxide had been produced in Zawar, India from the 12th to 16th centuries. This zinc was produced by reducing calamine using organic substances like wool.

Where did its name come from?

The name zinc comes from "zinn", the German word for tin.

Did You Know?

• A human body contains around 2.3g Zinc.
• The oldest evidence of pure zinc comes from Zawar, in Rajasthan, as early as the 9th century AD.
• Zinc is the fourth most common metal in use, trailing only iron, aluminium, and copper

Where is it found?

Foods and spices that contain the essential mineral zinc

Zinc is hard to find, because it is very reactive in its pure form, and makes up less than 1% of the earth's crust. It's found mostly in compounds like the mineral Zinc Sulfide, also known as sphalerite or zincblende.

What are its uses?

Zinc has many common and not-so-common uses: Zinc is used in many coins. Zinc is used to make brass and bronze. It is also used in metal coating and rust protection, called galvanization. It is also used in the batteries that power everything from flashlights to radio-controlled toys. This type of battery was invented by the French chemist George Leclanche more than 100 years ago. Zinc oxide is a common sunscreen because it can block harmful ultraviolet (UV) rays that damage skin. This same compound is also used to make white paints and to make photocopies. Zinc sulfide, another zinc compound, is used in electronic devices as a phosphor (pronounced "fos-four"). Phosphor gives off light when struck by electrons. Zinc sulfide has been used on the inside of computer and television screens to produce images from your favorite TV show to computer games.

Is it dangerous?

No, it is not dangerous. Zinc is necessary for the human body and helps boost your immune system. Zinc oxide can also be used as a sunblock to protect your skin from the damaging effects of ultraviolet light.

Other details about Zinc

Zinc has a boiling point of 907 degree Celsius and melting point of 419.53 degree Celsius.

References

== Rare Elements ==

Here all elements are listed alphabetically, together with a short description, which did not have their own chapter.

A

Actinium

Actinium has been detected in pitchblende.

Actinium is produced in nuclear reactors.

The word actinium comes from the Greek word for ray ("aktis"). It emits so much light that you can see a blue glow in the dark.

The half-life is the time it takes for half of a radioactive isotope to decay. The shorter the half-life, the more it radiates. longest-lived radium isotope ²²⁶Ra has a half-life of 1600 years, the longest-lived actinium isotope ²²⁷Ac has a half-life of 22 years. This time is long enough to make small batches of the substance. The Actinium obtained radiates very strongly. (Isotopes that only have a half-life of one second cannot be produced in large quantities.)

• 
  radioactive

Americium

Americium

The smoke detector contains Americium.

Americium is produced in nuclear power plants. (Few kilograms so far.) It is a radioactive and fissile element.

The longest-lived Americium isotope ²⁴³Am has a half-life of 7370 years.

• 
  radioactive

Astatine

DIMendeleevCab

|right|This element was drawn in Dmitri Mendeleev's periodic table.]]

If you bombard bismuth (picture) with helium nuclei, astatine is formed.

Astatine looks metallic. Astatine was synthesized by Dale Corson, Kenneth MacKenzie, and Emilio Gino Segrè at the University of California in 1940. In 1943 Berta Karlik and Traude Bernert discovered its natural occurrence. Greek means ἀστατέω = "to be unstable".

It is estimated that there are only 25 grams of astatine in the entire earth's crust. It is one of the rarest elements on earth.

In medicine (nuclear medicine) it is used, among other things, to treat malignant tumors. Astatine is radioactive and can be dangerous in significant amounts.

• 
  radioactive

B

Barium

barium fireworks

Some minerals fluoresce.

The element barium (from the Greek word for heavy) was extracted from the mineral barite. Barium containing minerals were discovered by an Italian shoemaker in 1602. This shoemaker, by the name of Vincenzo Casciarolo, studied nature alongside his work. He discovered that some stones glow after being left in the sun for a while. Water-soluble barium compounds are essential to life in small amounts and toxic in larger amounts. Barium nitrate is used for green fireworks and barium carbonate as a rat poison.

• 
  flammable
• 
  Warning

Berkelium

1.7 micrograms of berkelium

University of California, Berkeley

Berkelium is made in nuclear reactors. It's a very radioactive element.

• 
  radioactive

Bismuth

Bismuth

Philippus Theophrastus Aureolus Bombastus von Hohenheim, also called Paracelsus.

Bismuth (formerly also called bismuth) was described by Paracelsus (1493-1541) and shortly afterwards by Georgius Agricola (1494-1555). Some bismuth compounds were and are used in medicine: Against the pathogen that causes gastric ulcers, against bad breath and as a wound powder and skin ointment against inflammation, to stop bleeding and other things.

With the help of bismuth one can produce an alloy that melts at 70°C (Wood's metal). It is used in sprinklers for fire extinguishing.

• 
  flammable

Bohrium

Bohr atomic model of bohrium

Niels Bohr

This artificial element was named after Niels Bohr.

• 
  radioactive

Bromine

Brom

tear gas

Bromine means something like "stench" (Greek). Bromine is a liquid, orange nonmetal that emits corrosive fumes at room temperature. There are significant amounts of (harmless) bromine salt in seawater. These salts are used as plant fertilizers. Photo plates are coated with silver bromide.

• 
  acutely toxic
• 
  corrosive
• 
  Environment

C

Cadmium

Batteries contain cadmium (Cd)

The light meter contains cadmium.

The word cadmium is an old word for zinc ore that was partly used in medieval and ancient times. It was made in 1817 independently by Friedrich Stromeyer and Carl Samuel Hermann from different zinc ores. It is used for solar cells, semiconductors, for nickel-cadmium batteries and also for the construction of control rods in nuclear power plants. Cadmium and cadmium compounds are highly toxic. Therefore, many applications are banned in the EU. From the 1950s, zinc mines in Japan discharged their wastewater into rivers that were used to irrigate rice paddies. The rice farmers fell ill. They experienced severe pain. Kidney failure and bone softening often led to death. Because of the severe pain, it was called "Aua-Aua disease" (Japanese "Itai-Itai disease").

• 
  flammable
• 
  acutely toxic
• 
  Environment
• 
  Health hazard

Californium

Californium

1g californium is transported in this 50t container.

Californium is a radioactive element that is produced in nuclear reactors. The californium isotope ²⁵²Cf emits neutrons when it decays. These neutrons are used in cancer treatments, for industrial material studies, in the search for oil, in nuclear reactors and for the construction of atomic bombs.

• 
  radioactive

Caesium

Cesium is stored under airtight conditions.

Caesium indicates the beat of the atomic clock.

Cesium has special properties:

• It is the most reactive metal. It burns explosively when exposed to air.
• It is the softest metal.
• It is the heaviest stable alkali metal.
• It is one of the few gold colored metals.
• It has the second lowest melting point of any metal, after mercury.
• It is the "most punctual" ;-) element. Cesium is used in atomic clocks. The second is determined with cesium clocks.

Cesium was discovered in spring water in 1861 by Robert Wilhelm Bunsen and Gustav Robert Kirchhoff based on its blue spectral lines. They named the element after the Latin word for sky blue ("caesius"). Carl Setterberg was the first to produce pure cesium in 1881. Cesium is used in rocket ion engines.

• 
  flammable
• 
  corrosive

Cerium

Cer

rain of sparks

This element was discovered in parallel by different scientists in 1803. (Jöns Jacob Berzelius, Wilhelm von Hisinger, Martin Heinrich Klaproth). Carl Gustav Mosander produced pure cerium for the first time in 1825.

The word Cer, like the recently discovered planet Ceres, comes from the Roman goddess of agriculture and fertility, Ceres. Cerium generates sparks easily when rubbed, which can ignite smaller cerium crumbs. It is therefore used for lighters and also in films to produce an impressive shower of sparks. Iron alloys containing cerium are very ductile.

• 
  flammable
• 
  Warning

Copernicium

Page from Copernicus' manuscript on "The Earth Orbits the Sun".

Nicholas Copernicus (1473–1543

Named after Nicolaus Copernicus, this element was artificially produced and researched.

• 
  radioactive

Chromium

Chrome is a hard, malleable metal and is lustrous silver in color.

Chrome car rim.

In 1779, Louis-Nicolas Vauqueli extracted the metal chromium from the mineral crocoite.

Crocoite

The name chrome comes from the Greek word chrṓma (χρώμα), which means color. (The "color" of the tones, i.e. their sound, was also described in this way.)

Dyes can many dyes be made from chromium. A human body contains chromium. Most chrome ore is found in South Africa.

post yellow

Chromium compounds are used in the manufacture of dyes. Commonly used: postal yellow and chrome green. Bicycle handlebars and car bumpers are coated with the silvery chrome. They look great and won't rust. Chromium is particularly important for steel production. Chrome vanadium steel does not rust and is very strong. Chromium salts are also used to tan leather.

Chromium itself is non-toxic, but some chromium compounds (e.g. the chromates) are toxic and carcinogenic.

• 
  Environment

Curium

Curium spectrum visible

Pierre and Marie Curie

Curium is an artificial element made in nuclear reactors. It is radioactive and fissile.

This element was named after Pierre and Marie Curie. We have the two scientists to thank for many insights into the structure of our matter.

• 
  radioactive

D

Darmstadtium

nuclide map with color-coded scale of half-life

congress center darmstadtium

Darmstadtium is an artificial element that was created in Darmstadt in 1994.

• 
  radioactive

Dubnium

Dubnium decay scheme

The House of Scientists in Dubna

Dubnium/Db is artificially created by shooting atomic nuclei together. There are several ways to make dubnium:

$\mathrm {{}_{\ 95}^{243}Am+{}_{10}^{22}Ne\rightarrow 5\,{}_{0}^{1}n+{}_{105}^{260}Db}$

$\mathrm {{}_{\ 95}^{243}Am+{}_{10}^{22}Ne\rightarrow 4\,{}_{0}^{1}n+{}_{105}^{261}Db}$

$\mathrm {{}_{\ 98}^{249}Cf+{}_{\ 7}^{15}N\rightarrow 4\,{}_{0}^{1}n+{}_{105}^{260}Db}$

$\mathrm {{}_{\ 98}^{250}Cf+{}_{\ 7}^{15}N\rightarrow 4\,{}_{0}^{1}n+{}_{105}^{261}Db}$

$\mathrm {{}_{\ 97}^{249}Bk+{}_{\ 8}^{16}O\rightarrow 4\,{}_{0}^{1}n+{}_{105}^{261}Db}$

$\mathrm {{}_{\ 97}^{249}Bk+{}_{\ 8}^{18}O\rightarrow 5\,{}_{0}^{1}n+{}_{105}^{262}Db}$

• 
  radioactive

Dysprosium

Dysprosium

spectrum of dysprosium

This element was named after the Greek word for difficult to access (dysprósitos). This has the following reason: Dysprosium belongs to the rare earths. The rare earths react chemically in a very similar way. In nature, they are usually found mixed together. It's hard to separate them. The discoverer of this element, Paul-Émile Lecoq de Boisbaudran, found dysprosium in 1886 using spectral analysis. But he only caught the light that this element emits, he couldn't get it pure. It was only in 1906 that Georges Urbain was able to obtain the element.

• 
  flammable

E

Einsteinium

Einsteinium iodide transmits light.

Albert Einstein, 1921

Einsteinium is formed in nuclear power plants and when hydrogen bombs explode. This element was named after Albert Einstein, the developer of the theory of relativity.

• 
  radioactive

Erbium

Erbium

erbium oxide

Like some other rare earths, erbium oxide is used to color glass and ceramics.

• 
  flammable

Europium

Europium

The euro note glows in UV light.

Appropriately, europium is used to protect against counterfeiting in euro banknotes. It fluoresces in UV light. Europium was also used in screens and mercury vapor lamps.

• 
  flammable

F

Fermium

Traces of fermium are in the cloud from the hydrogen bomb detonated in 1952.

Elutionskurven Fm Es Cf Bk Cm Am

Fermium is radioactive and its isotopes have a short half-life (maximum 100 days). Fermium was created in atomic bomb explosions, in nuclear power plants, and in the laboratory.

Small atoms can be made into larger atoms by adding particles (neutrons). This process takes place in nature in stars and especially in stellar explosions (->supernova). This is how the other elements were formed from the small hydrogen atoms.

This process can be reproduced in the laboratory. Up to the element fermium, the atoms can absorb neutrons and grow larger. The heavier elements decay immediately when neutrons are added. Even heavier elements can only be produced by shooting two atomic nuclei at each other.

• 
  radioactive

Flerovium

Russian stamp

Only a few atoms of flerovium have been produced. It was named after Georgi Nikolayevich Fleorov.

• 
  radioactive

Francium

Uranite contains traces of Francium

electron shells of Francium

Francium has an electron on the outer shell and is therefore an alkali metal. Its properties can therefore be predicted, but are difficult to verify since only tiny amounts of this element exist.

• 
  radioactive

G

Gadolinium

Gadolinium

Lepersonnite forms yellow crystals.

Gadolinium is a rare element. The mineral lepersonnite-(Gd) contains this element. This mineral has a complex chemical composition: Ca(Gd,Dy)₂(UO₂)₂₄(SiO₄)₄(CO₃)₈(OH)₂₄ 48 H₂O.

• 
  flammable

Gallium

Gallium.

LEDs (light-emitting diodes) contain gallium.

Gallium is a rare, silvery-white metal. About 100 tons of it are produced per year. It is used for the production of light emitting diodes and solar cells. Paul Émile Lecoq de Boisbaudran first produced this element in 1875. When naming it, he killed two birds with one stone: he named the fabric both after his country and after himself: both "France" (Gaul) and "Lecoq" (rooster) are called "Gallus" in Latin. This metal can also be used to make a teaspoon that melts in a cup of hot tea.

• 
  corrosive
• 
  Danger

Germanium

Germanium made by Winkler

germanium

The semi-metal germanium is used in the construction of transistors. In 1886, the German chemist Clemens Winkler produced germanium at the Bergakademie in Freiberg. He named it after the Latin name of his native country. Attention: Germanium powder burns.

• 
  flammable

H

Hafnium

Hafnium

Nautilus, the first nuclear submarine

Hafnium burns with a very bright light and is used in special flash lamps. Hafnium electrodes are used for welding. Some hafnium compounds are very hard.

Hafnium is used in large quantities in nuclear reactor control rods for nuclear submarines.

• 
  flammable

Hassium

GSI-Darmstadt

GSI

Hassium is a man-made element.

• 
  radioactive

Holmium

Holmium

Holmium oxide

Holmium is used for high-power magnets, in lasers, and for control rods in breeder reactors.

• 
  flammable

I

Indium

indium wire.

LED contains indium

Indium emits light with a blue, indigo spectral line. It was discovered by Ferdinand Reich and Theodor Richter in 1863. With few known indium deposits and much indium being consumed, it is the metal that may be the first to become depleted. It is used in aircraft, nuclear power plants and transistors. The metal does not burn, the powder is combustible. Indium can cause growth disorders in embryos.

• 
  flammable
• 
  Warning

Iridium

Iridium

Dinosaur skeletons

Iridium is heavy and is therefore found in the Earth's core and in some meteorites. At the end of the Cretaceous period, dinosaurs and many other creatures became extinct. The deposits of the sedimentary layer that marks the end of the Cretaceous are rich in iridium. An indication of a massive meteorite impact. The impact crater is in Mexico.

Iridium takes its name from the Greek word for rainbow (iris). It is used in alloys that need to be particularly hard, such as the ball of a ballpoint pen. It is also used in spark plugs, jewelry, as a catalyst, and in the UV coating of sunglasses.

• 
  flammable
• 
  Warning

K

Krypton

lamp contains krypton

The Geiger counter contains krypton

Krypton (atomic number 26) is one of the rarest elements and could only be obtained in tiny amounts with great effort. The explorers Ramsay and Travers therefore named it after the Greek word kryptós, which means "hidden". Krypton is used in halogen lamps. Although krypton is a noble gas, it can form compounds (krypton difluoride).

Kryptonite, dangerous for Superman, is made from a made-up element called kryptonium (atomic number 126).

• 
  gas bottle

L

Lanthanum

Lanthan

These flints contain lanthanum

Lanthanum (Greek λανθάνειν, lanthanein, "to be hidden") was discovered in 1839 by the Swedish chemist Carl Gustav Mosander. He grew crystals from cerium nitrate in 1839. To his surprise, another crystal form formed. Another element was obviously hidden in the cerium nitrate. Mosander named it lanthanum after the Greek word for "hidden". It is used in glasses and in flints.

• 
  flammable

Lawrencium

Zyclotron

Magnet for a cyclotron

Lawrencium, named after the inventor of the cyclotron, is made by colliding atomic nuclei in a cyclotron.

• 
  radioactive

Livermorium

Only a few atoms of livermorium were produced. The element was named after the Lawrence Berkeley National Laboratory (LLNL) in California, USA.

• 
  radioactive

Lutetium

Lutetium

Lutetium-phthalocyanine

Lutetium is difficult to obtain and therefore expensive. It is not used on a large scale but mostly only for scientific experiments.

• 
  flammable

M

Meitnerium

PHELIX-Laser

Lise Meitner 1946

Meitnerium is a man-made element.

• 
  radioactive

Medelevium

Medelevium was made in this cyclotron.

This drawing shows how a cyclotron works.

Mendelevium, named after Dmitri Ivanovich Mendeleev, is made by colliding atomic nuclei. For this, Einsteinium²⁵³Es is bombarded in a cyclotron with accelerated helium nuclei⁴He. This creates Mendelevium²⁵⁶Md and a neutron.

• 
  radioactive

Molybdenum

molybdenum

This biocatalyst contains molybdenum.

Molybdenum was named after the Greek name for lead. Molybdenum tolerates high temperatures and is used for steel alloys. It is used as a catalyst in the petroleum industry. Many living things also use molybdenum in bio-catalysts. Some bacteria produce fertilizer from atmospheric nitrogen. For this you need molybdenum (formula Mo). (see picture) Pieces of metal do not burn, but powder burns easily.

• 
  flammable

Moscovium

Moscow

Only a few atoms of moscovium were produced. The element was named after the city of Moscow.

• 
  radioactive

N

Neodymium

Neodym

neodymium compound

Neodymium - the "New Twin" - is one of several chemisch similar substances. Neodymium, like its twins, can be used for magnets. Neodymium powder burns.

• 
  flammable
• 
  Warning

Neptunium

neptunium (shiny) in uranium shells (tarnished black).

Image of Voyager 2 from the planet Neptune.

Neptunium is created in nuclear reactors and can be used as fuel in nuclear reactors and also in the construction of atomic bombs. There are about 20 different neptunium isotopes. The longest-lived isotope is ²³⁷Np with a half-life of 2.144 million years.

• 
  radioactive

Nihonium

Kosuke Morita and Hiroshi Matsumoto

A few atoms of nihonium were artificially produced. Nihon means "Japan" (Japan) in Japanese.

After the discovery, the element was first given the systematic name ununtrium (chemical symbol Uut), a formation from Latin unum for 'one' and Latin tria for 'three', corresponding to atomic number 113. It was also called eka-thallium, composed of Sanskrit eka for 'one' and thallium, with reference to its classification in the periodic table 'a place below thallium'.

• 
  radioactive

Niobium

The middle contains niobium.

The nozzle contains niobium.

The elements niobium and tantalum always occur together in ores. This element was named after Niobe, daughter of Tantalus. This element was independently studied and given different names by two chemists: Charles Hatchett (1801) Heinrich Rose (1844). The IUPAC is responsible for naming the elements. It was not until 1950 that the name niobium was agreed upon. Niobium serves as a steel alloy and is used in jewelry and coins. Niobium does not burn, but niobium powder is combustible.

• 
  flammable

Nobelium

Nobelium is created in a cyclotron.

Alfred Nobel

Only a few thousand atoms of the element nobelium have been produced to date.

• 
  radioactive

O

Oganesson

Yuri Oganesyan

Only a few atoms were made of the element oganesson. It was named after Yuri Zolakovich Oganesian.

• 
  radioactive

Osmium

Osmium

Artificial Heart Valves

Osmium is durable, hard and heat resistant, but also quite expensive. Some artificial heart valves contain an osmium alloy. Like tungsten, it used to be used in light bulbs.

• 
  flammable
• 
  corrosive
• 
  Warning

P

Palladium

Palladium

autocatalyst

Palladium was named after the recently discovered asteroid Pallas, which in turn was named after the Greek goddess Pallas Athena. William Hyde Wollaston, who gave the name, extracted the element from platinum ore in 1803. Palladium is used as a catalyst. So it destroys toxic gases in the exhaust of the car. Good white gold alloys contain palladium in addition to gold. White gold is used for coins, dental crowns and jewellery.

Amazingly, the solid metal palladium has cavities inside. Hydrogen gas can therefore flow through hot palladium sheets as if through a sieve and thus be separated from other gases. If you put a piece of palladium in a compressed gas bottle and fill it with hydrogen, the palladium absorbs the hydrogen like a sponge. One liter of palladium solutions can store three thousand liters of hydrogen. (Tank for hydrogen cars.) Chunks of palladium do not burn, but powder burns easily.

• 
  flammable
• 
  Warning

Polonium

The mineral pitchblende contains polonium.

Polonium in a cloud chamber. The radioactive radiation creates fog trails.

Radioactive elements turn into other, lighter elements. They emit radiation. In some mines, miners breathe in the radioactive gas radon. When radon decays, it turns into the metal polonium. Polonium can cause lung cancer. It was used as a neutron source in the atomic bombs that destroyed Hiroshima and Nagasaki.

• 
  radioactive

Praseodymium

Praseodymium - compound

Praseodym

"Leek Green Twin" is the translation of the name of this element. If you look at the pictured praseodymium compound, the designation leek green (Greek: prásinos) becomes clear. But what is the meaning of the word twin (Greek: didymos)? In 1874, Per Teodor Cleve recognized that the substance obtained by Carl Gustav Mosander was two different substances that resembled each other almost like twins.

Praseodymium is used to build powerful magnets. Praseodymium powder burns.

• 
  flammable

Promethium

Prometheus brought the fire of the gods to mankind. As punishment he was chained but, as shown here, freed by Heracles.

Image of the Hiroshima dome.

Promethium is formed through the radioactive decay of other elements such as uranium. There is about 570g of promethium, finely distributed, all over the world. (The amount was not actually found, but only determined by calculation.) In recent decades, enough promethium has been produced in nuclear power plants that chemical experiments could be carried out with it. Promethium is a silvery heavy metal that reacts similarly to neodymium.

Some atomic bomb builders saw themselves in the role of Prometheus: they brought nuclear fire to mankind. (Read at Richard P. Feynman.)

The discoverers of this element, on the other hand, had a different intention: They named the element after Prometheus as a warning against the nuclear arms race.

• 
  radioactive

Protacinium

uranite

Otto Hahn and Lise Meitner, 1913

In the mineral uranium, the element uranium decays and the element protacinium (^234mPa) is formed for a short time, which quickly (half-life: 1.17 minutes) decays into actinium. This isotope was discovered by Kasimir Fajans and Oswald Helmuth Göhring in 1913. A long-lived isotope of the element protacinium (²³¹Pa) was discovered by Otto Hahn and Lise Meitner in 1918. (Half-life: 32,760 years)

• 
  radioactive

R

Radium

Uranite contains radium.

In 1925 there were cosmetics containing radium

Radium comes from the Latin word for ray ("radius"). The element radium decays, emitting alpha rays (helium nuclei), beta rays (electrons), and gamma rays (X-rays). All elements that emit such rays are called radioactive. Radium was first used as a medicine and in cosmetics. It took several years before the dangers of radioactive radiation were recognized and almost thirty years before radium was no longer used for it. Radium was discovered by Henri Becquerel and studied in detail by Marie and Pierre Curie. (They died as a result of the radiation.)

• 
  radioactive

Rhenium

Rhenium

turbine blades

Rhenium, from the Latin word for the river Rhine (rhenus), is added to alloys to improve them. Due to the high forces, turbine blades can deform (technical term: "creep") or even break (technical term: "fatigue"). Thermocouples are made from an alloy of platinum and rhenium. With them you can withstand high temperatures (up to 2200°C) measure. It is also used for heating wires and incandescent lamps.

Rhenium metal does not burn, but rhenium powder does.

• 
  flammable

Rhodium

Rhodium powder is combustible.

White gold ring with rhodium plating

Platinum ores often contain chemically similar elements. In 1803, William Hyde Wollaston extracted rhodium from platinum ore. It is used as a catalyst and as a coating for jewelry. A thin layer of rhodium prevents metals from tarnishing and gives it a silvery sheen. Rhodium can also be used to make mirrors. Pieces of metal do not burn, but powder burns easily.

• 
  flammable

Roentgenium

original part of the 120 meter long UNILAC

Wilhelm Conrad Roentgen

Roentgenium is a man-made element. It was named after Wilhelm Conrad Roentgen.

• 
  radioactive

Rubidium

Rubidium is stored in an oxygen-free environment.

Kirchhoff Bunsen Roscoe 1862 (from left)

All atoms emit a light that is typical for them. Rubidium emits a purple-red light. Using this light, Robert Wilhelm Bunsen and Gustav Kirchhoff discovered rubidium in 1861. Bunsen then extracted 9 g of rubidium salt from 44,200 l of spring water. (The Latin word for red is "rubidus". This is also where the gemstone ruby got its name.) Rubidium is used for a few applications such as some vacuum tubes. Rubidium burns in air and explodes when quenched with water.

• 
  flammable
• 
  corrosive

Ruthenium

Ruthenium

These resistors contain ruthenium.

Ruthenium was named by the element's discoverer, Karl Ernst Claus, after the Latin name for Russia (ruthenia). Tiny amounts of this substance improve the quality of steel alloys and protect them from rusting. Ruthenium is also used to make hard drives and as a catalyst. Pieces of metal do not burn, but powder burns easily.

• 
  flammable

Rutherfordium

Atomic model of Rutherfordium

Rutherfordium is a man-made element that has a short half-life. It was named after Ernest Rutherford, who provided an impetus for the development of other atomic models with a simple atomic model.

• 
  radioactive

S

Samarium

Samarium

Samarium is extracted from the mineral samarskite. This mineral was named in 1847 after the mining engineer who discovered it. Elements were often named after Greek and Roman deities in the past. This element was the first to be named after a human.

The mineral samarskite contains uranium and has therefore been mined in significant quantities. The by-product samarium is used in lasers, magnets and as a catalyst.

• 
  flammable

Seaborgium

Alchemists' element symbols

Glenn T. Seaborg

This man-made item was nach named Glenn T. Seaborg. Seaborg succeeded in producing gold atoms in 1980. The alchemists were already pursuing this goal.

• 
  radioactive

Selenium

selenium (black, gray, red

selenium rectifier

Selenium is a metalloid and comes in three forms (modifications): There is silver-grey metallic selenium, black non-metallic selenium and red non-metallic selenium. It was discovered by Jöns Jakob Berzelius in 1817. The word "selenium" comes from the Greek name of the moon "Selene". It is used for building semiconductors and for exposure meters. In small traces, selenium is essential for life, in larger amounts it is acutely poisonous. Selenium can also cause significant organ damage (liver, heart).

• 
  acutely toxic
• 
  Health hazard

Strontium

Strontium destilled crystals

Strontium colors flames red.

A strontium-bearing mineral was discovered and studied by Adair Crawford in Strontian (Scotland) in 1790. Strontium salt is used in the aluminum industry and to make fireworks. It is sometimes found in anti-inflammatory toothpaste. Strontium is also used in some vacuum tubes. About 500,000 tons of strontium salt are mined every year.

Strontium fires cannot be extinguished with either water or carbon dioxide.

• 
  flammable

T

Tantalum

Tantal

Tantal capacitors

Tantalum hardly reacts, it is largely chemically inert. Tantalum oxide does not react with water or acids. Figuratively speaking, tantalum oxide is incapable of quenching its thirst. In Greek mythology, the evil Tantalus could not quench his thirst as punishment for his misdeeds. This element was therefore named after him.

Tantalum powder burns.

• 
  flammable

Technetium

Uranium ore contains technetium.

Technetium is produced in the fuel element.

This element was discovered in minerals in 1925. Technetium is the first (1937) man-made element and got its name from the Greek word for artificial (τεχνητός / technētós). In nuclear power plants, technetium forms as radioactive waste. Approximately 80 t of technetium have accumulated to date. Some of its isotopes have a half-life of around 200,000 years. In small amounts it is used in nuclear medicine.

• 
  radioactive

Tellurium

Tellur

Some detonators contain tellurium.

Tellurium comes from the Latin word "tellus" which means earth. It was made in 1782 by Franz Joseph Müller von Reichenstein. It is used as an additive to alloys and the oxide as a glass.

• 
  acutely toxic

Tennessine

Seal of Tennessee

Only a few atoms were made of the element tennessine. It was named after Tennessee, USA.

• 
  radioactive

Terbium

Terbium

Terbium is extracted from monazite sand.

Terbium is used in magnets and to dope semiconductors.

• 
  flammable

Thallium

Thallium reacts easily with air and corrodes.

Pat Poision

Thallium is used for lenses in photocopiers and photocells.

Thallium is highly toxic. Possible course of poisoning in humans:

2nd-3rd Day: Alternating diarrhea and constipation.

2nd week: hair loss

2nd-3rd week: blurred vision, excessive pain perception, abnormal heart rhythm, muscle weakness (can result in death) After the vPoisoning often results in permanent damage to health: disturbed reflexes, muscle atrophy. Even chronic poisoning with small amounts poses a significant health risk!

A thallium compound was previously used as a rat poison because it has a delayed effect and the rats do not realize that the baits are poisoned. (Young rats have to eat something as "tasters". If they get sick, no other rat will eat it.)

• 
  acutely toxic
• 
  Health hazard

Thorium

Monazite contains thorium.

Jöns Jakob Berzelius

Elements can have different numbers of neutrons in the nucleus. They are called isotopes. Chemically, they react in the same way, but they have different lifespans. (The half-life is how long it takes for half of the substance present to decay.) To the chemist, isotopes with a very, very long half-life are no different from normal, stable elements. You can find ores, extract them and experiment with them.

Thorium was discovered by Jöns Jakob Berzelius in 1829. It's a radioactive element. Its longest-lived isotope ²³²Th has a half-life of 14,050,000,000 years. Because of its long half-life, it is also found in the earth and because of its long half-life, this thorium isotope emits very little (low dose rate).

Therefore, the danger of thorium was misjudged. The harmfulness of the radioactive radiation was not recognized at first and then it took several years until the radioactive substances were no longer used in everyday goods. Thorium was used in mantles, welding electrodes, glow electrodes. Thorium glass lenses have special optical properties. Thorium dioxide was even used as an X-ray contrast medium: the contrast medium containing approx. 5g thorium was injected into the patient's veins before the X-ray was taken. Many patients developed cancer after 30-35 years. (The thorium is stored in the body. It takes 22 years for half of the stored thorium to leave the body: biological half-life.)

Thorium is also suitable for use in nuclear power plants. In the nuclear power plant, the thorium isotope ²³²Th is irradiated with neutrons ¹n and turns into the thorium isotope ²³³Th. (Calculation: 232+1=233). This highly radioactive thorium isotope has a half-life of 22 minutes and decays to fissile uranium in two steps. Nuclear power plants that use thorium generate a lot of nuclear waste and facilitate the construction of nuclear bombs (technical term: proliferation).

However, it is also possible to use thorium to destroy nuclear-grade plutonium (keyword: MOX fuel element).

• 
  radioactive

Thulium

Thulium

dosimeter

Thulium is named after the island of Thule. This island was discovered far to the north in ancient times and later associated with many myths.

Thulium is used in dosimeters to measure radioactive emissions. It is also used in scintillators and lasers.

• 
  flammable
• 
  Warning

X

Xenon

Xenon lamp

Ion Engine with Xenon.

Xenon can be used as a fill gas in lamps to increase the life of the tungsten filaments and also the luminous efficacy. There is also an application in headlights, which, in contrast to incandescent lamps, have a higher light output with lower energy requirements. Xenon is used in excimer lasers.

• 
  gas bottle

Ytterbium

Ytterbium

Galissard de Marignac discovered ytterbium in 1878.

Ytterbium is used in specialty steel, lasers, and magnets. The best permanent magnets contain ytterbium.

• 
  flammable
• 
  Warning

Y

Yttrium

Yttrium

Yttrium mineral

In 1794, Johan Gadolin found an ore in the Ytterby mine in Sweden, from which yttrium was extracted. In 1824, Friedrich Wöhler extracted the element yttrium from it. Yttrium is one of the rare earths (which are not that rare). It is used for magnets, fuel cells and spark plugs. Yttrium powder can build up in the lungs and damage them. Pieces of metal do not burn, but powder burns easily.

• 
  flammable
• 
  Danger

Z

Zirconium

Zirconium

Zircon

The zircon gemstone can have many colors due to the addition of other elements: colourless, red, yellow, green, blue, brown or black. This gemstone has been used since ancient times. It can easily be confused with the diamond and is sometimes sold by scammers as a "real" diamond. Experts can easily tell them apart, as zircon is not nearly as hard as diamond. Zirconium is used for steel alloys and in nuclear power plants. Pieces of metal do not burn, but powder burns easily.

• 
  flammable

License

Version 1.3, 3 November 2008 Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. <http://fsf.org/>

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

1. APPLICABILITY AND DEFINITIONS

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The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.

The "publisher" means any person or entity that distributes copies of the Document to the public.

A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

2. VERBATIM COPYING

You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and you may publicly display copies.

3. COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

4. MODIFICATIONS

You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
4. Preserve all the copyright notices of the Document.
5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice.
8. Include an unaltered copy of this License.
9. Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
11. For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
13. Delete any section Entitled "Endorsements". Such a section may not be included in the Modified version.
14. Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section.
15. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements".

6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

8. TRANSLATION

Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License.

However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.

Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.

Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, receipt of a copy of some or all of the same material does not give you any rights to use it.

10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Document.

11. RELICENSING

"Massive Multiauthor Collaboration Site" (or "MMC Site") means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A "Massive Multiauthor Collaboration" (or "MMC") contained in the site means any set of copyrightable works thus published on the MMC site.

"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization.

"Incorporate" means to publish or republish a Document, in whole or in part, as part of another Document.

An MMC is "eligible for relicensing" if it is licensed under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008.

The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing.

How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

Copyright (c) YEAR YOUR NAME.

Permission is granted to copy, distribute and/or modify this document

under the terms of the GNU Free Documentation License, Version 1.3

or any later version published by the Free Software Foundation;

with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.

A copy of the license is included in the section entitled "GNU

Free Documentation License".

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the "with...Texts." line with this:

with the Invariant Sections being LIST THEIR TITLES, with the

Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.