As you already know, all matter is made up of atoms or groups of atoms (molecules) bonded together in a particular way. In order to understand the nature of electrical charge we need to consider a simple model of the atom. This model, known as the Bohr model (see Figure 19.1), shows a single atom consisting of a central nucleus with orbiting electrons.
Within the nucleus there are protons which are positively charged and neutrons which, as their name implies, are electrically neutral and have no charge. Orbiting the nucleus are electrons that have a negative charge