Atoms are the smallest particles of an element that can take part in a chemical reaction.
All atoms contain sub-atomic particles namely; electrons, which are found in the energy levels and protons and neutrons which are found in the nucleus of an atom.
Atoms of the same elements may have different neutrons but the same number of protons or atomic number, these atoms are called isotopes.
Additionally, atoms may have different number of electrons but the same number of protons, when they form ions.
