So suppose we begin with a neutral atom in which the number of electrons equals number of protons. Now, what that basically means is that if we add up our charges due to our electrons, with the charges due to our protons, we're going to get a net charge or an overall charge of zero. Now, that's exactly what a neutral atom is. It's an atom. Atom in which our charge is zero. Well, now, suppose we take our atom and our neutral atom gains or loses electrons.