What are Chemical Elements and Compounds?

Chemical Elements and Compounds Explained

Elements formed in stars at the point when the universe was created.

Iron, silver, gold, beryllium, hydrogen, carbon, nitrogen and oxygen are some of the 118 known chemical elements.  The full list can be found in the Periodic Table. 

An element is the simplest known substance.  This means it cannot be broken down through a chemical reaction.

A chemical reaction causes a substance to change into one or more different substances.

An element contains one type of atom.  An atom is the smallest particle of a chemical element.

When the same types of atoms come together, they create an element.

Oxygen is a chemical element because it only contains oxygen atoms. 

When more than one chemical element is present it becomes known as a chemical compound.  A compound is two or more chemical elements that have been combined.

An example of a chemical compound is water, which is made up of two hydrogen atoms and one oxygen atom.

When two or more atoms bond together they form a larger particle known as a molecule.  It can take many thousands of atoms to form a single molecule.

Molecules can be different shapes and sizes.  When many stack together in an orderly, repeating arrangement, they form a crystal lattice which extends in all directions.

The lattice is the highly ordered arrangement of atoms that forms a crystal.

Most minerals are chemical compounds which means they're made up of two or more chemical elements.  Minerals made up of a single element are known as native elements.  Examples of native elements include copper, carbon, gold, titanium, sulphur, chromium and vanadium.

An element can be a liquid, solid or gas.  Bromine and mercury are the only liquids.  Oxygen and hydrogen are gases.

Chemical compounds can also be liquid, solid or gas.  Water is hydrogen and oxygen, carbon dioxide is carbon and oxygen.  Solid chemical compounds are minerals. 

Quartz is a solid chemical compound because it's made up of silicon and oxygen.  Halite, better known as salt, is another because it's made up of one atom of the element sodium and one of chlorine.