Atoms and Molecules

Everything you can see, touch, taste or breathe is made of atoms — particles so unimaginably small that a single full stop on this page contains many billions of them. Atoms are the fundamental building blocks of all matter in the universe, from your body to distant stars.

Although atoms are tiny, they have a structure of their own. At the centre is a dense core called the nucleus. Whizzing around the nucleus are even tinier particles called electrons. Most of an atom is actually empty space between the nucleus and the electrons.

The nucleus is made of two kinds of particle. Protons carry a positive electric charge, and neutrons carry no charge at all. The electrons orbiting outside carry a negative charge. In a normal, balanced atom, the number of protons equals the number of electrons, so the charges cancel out.