The principle states that two electrons cannot have the same quantum numbers. And i've read that this applies to "fermions"- protons, neutrons, 1/2 spin particles. But how exactly does this apply to, say, a proton? Sorry if I sound stupid....I've got all my knowledge about this through the internet. I'm in the 10th grade as well. So I'm not too fimiliar with the complex stuff :') Thanks!