I am a mathematics student who is doing an introductory course in nuclear physics and since the course is rather elementary a lot of the definitions/derivations are skipped which makes it quite tough to understand a lot of stuff. So here is a question which I don't understand:

We are studying scattering experiments on the nucleus by using probes like electrons and neutrons. If I am not mistaken, the electrons give us information on the charge distribution and neutrons give us information on the matter distribution. However I don't fully understand what we mean by charge/matter distribution?