The three subatomic particles are electrons, protons and neutrons. Protons are positively charged and have a relative mass of 1 whilst neutrons are neutral in charge and also have a positive charge of 1. Electrons are negatively charged and have a relative mass of 1/1835. In the atomic model, electrons are found moving around the nucleus on 'rings' described as energy levels. Protons and neutrons are both found in the centre of the atom and make up what we call the nucleus of the atom.