Everything is made from atoms, including you. Atoms are tiny particles that are far too small to see, even with a microscope. If people were the same size as atoms, the entire population of the world would fit into a box about a thousandth of a millimetre across!

We usually imagine atoms as being like tiny balls:

To make diagrams simpler we often draw atoms as circles:

Elements

There are over a hundred different types of atom, and these are called elements. Each element has a special name. For example carbon, oxygen and hydrogen are all elements.

Lead and gold are elements too. A piece of pure gold contains only gold atoms. A piece of pure lead contains only lead atoms.

Chemical reactions join or split atoms to rearrange them. But they cannot change one element into another element, or anything simpler. A chemical reaction cannot turn lead into gold, becuse it can't change the atoms into different elements.