Parts of the Atom

Atoms are really small and make up everything around us:

  • At the centre is a nucleus made up of protons (positive) and neutrons (neutral)

  • This is surrounded by shells of electrons (negative)

Representing Atoms

This is how we can show the number of different types of particles in a particular atom.


You should remember that:

  • Atoms have an equal number of protons and electrons

  • Ions have a different number of protons and electrons, so are positive or negative

  • Isotopes are atoms with the same number of protons but a different number of neutrons

Representing Atoms: Example

This is how to work out the number of particles in some atoms and ions.

The Alpha Scattering Experiment

An in-depth look at the experiment that led to the nuclear model of the atom.

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