One of the dot points tells us to assess Pauli's contribution to the development of the atomic theory. I've read over a few sets of notes and they all speak about the same things - the Exclusion Principle; how two electrons cant have the same set of quantum numbers, etcetc. For some reason I don't get what any of that means, or how it contributes to the atomic theory at all. Can someone help out by explaining it in more simple terms, so I can understand exactly what he did? Thanks