There are three elementary particles that make up the atom. Those being: the proton, the neutron, and the electron. Both the proton and the neutrons are nucleons, and they reside in the nucleus. The electron orbits the nucleus, a little like how the planets orbit the sun. An atom has an overall charge of one, as the singly positive protons and singly negative electrons cancel each other out, as in an atom there are equal numbers of protons and electrons.