this is for a hydrogen atom, now. yes. let's supposed i have a helium atom. now, we got two protons. it turns out there's two neutrons here too. and you know what? you know what's gonna happen to this space over here? take one guess. everyone. everyone. this charge out here now sees two protons tugging on it. how many say, "it'll be pulled into a tighter orbit"? how many say, "no, no, no, it'll stay the same"? how many say, "no, it'll be pushed further away"? check your neighbor. -- how many say it's gonna be tighter? yay, that's right. and it turns out, for a helium atom, the helium will hold the electron tight. and furthermore, it will hold another one too. the fact it holds another one makes it a little bit bigger, okay, 'cause they're repelling over here. but a helium atom is smaller. it turns out a helium atom won't gang up with any other atom, so there's no such thing as a helium molecule. we have two positive charges right next to each other like that, how do you deal with that? why don't those two positive charges repel? why don't they repel? look how