 So, let's use molecular orbital theory to see if the molecule H2 exists, okay? So from Vesper theory, we already know that it does, like you just told me, okay? So if I wanted to draw H2, it would look something like that from Vesper theory, right? Okay, so let's do molecular orbital theory and build that molecule, okay? So H, so doing molecular orbital theory, we have to build the atomic orbital diver, okay? Hydrogen only has the one electron and it's 1s orbital, right? So, hydrogen, 1s orbital, one electron, like that. Everybody okay with that? On the other side, we have a 1s orbital and a hydrogen with one electron, like that. Okay, so that gives us H plus H equals H2, right? Is everybody okay with that? So when you do this, you have to make two orbitals, so two molecular orbitals. Normally we call it a bonding orbital, but then we call it anti-bonding orbital, okay? So let's do that, whatever. Okay, so the bottom one's called the bonding orbital. And remember that's the sigma bond that's being first, okay? So sigma, we call it sigma 1s orbital. This anti-bonding orbital, we call it sigma star 1s. So how many electrons can go into any orbital? Two, right? So of our rules, off-bouhons, poly-exclusion, so remember this is energy getting higher. So the atomic orbitals are actually at a higher energy than that bonding molecular orbital. So what these electrons will do is fill that orbital like that, okay? So hopefully you can see we've made a bonding orbital filled, okay? So whatever this bonding orbital does, if we put electrons up here in the anti-bonding orbital, it undoes what the bonding orbital does, okay? So in order to figure out if this molecule would exist or not, we have to figure out what the bond order of this is, okay? So how do we do bond order? Bond order is one-half of the bonding electrons minus that anti-bonding electrons, okay? So one-half, how many bonding electrons do we have? Two. Two, and anti-bonding? Zero. Zero. So one-half times two is what? So that's how many bonds there's going to be between those two hydrogen atoms. So notice it correlates very nice with what we know from Vesper here, okay? That there's a one bond in between those two hydrogen atoms, okay? So does this molecule exist or does it not exist? It does. It exists, yes, it exists, okay? And now let's write it's electron configuration, okay? So how do we write the electron configuration? I haven't taught you yet, but now I'm going to, okay? So how do we write the electron configuration? Sigma, one-S, so you got to put it in parentheses, sigma, one-S, and there's two electrons in it, okay? If there was any electrons here, then we would have put sigma star one-S, okay? However, many electrons were in there. Okay, is everybody okay with that? That's the electron. Any questions on this?