Atom

Key Stage 3

An atom is a very small particle made of protons, neutrons and electrons that can join with other atoms to make molecules.

In The Dalton Model atoms are shown as ball shaped particles. This makes it easier to draw diagrams of molecules.


A picture of The Dalton Model of an atom.

Atoms are made of three smaller particles; the proton, neutron and electron.

Protons and neutrons are found in the nucleus at the centre of an atom. Electrons are found orbiting the nucleus in 'shells'.


A diagram of an atom.

In an atom the number of protons is always the same as the number of electrons.

Different atoms can have different numbers of protons and neutrons.

The simplest atom is Hydrogen which has 1 proton and 1 electron and no neutrons.