 So, let's try another one of these molecular orbital theory problems. This time we're going to do BE2 plus, so beryllium 2 plus. So, remember when we're doing the bonding, anti-bonding electron diagram, so we want to only concentrate on the valence electrons, okay? So, we're looking at the valence electrons for beryllium, right? So, we have two beryllium atoms here. What are those valence electrons? The orbitals are those valence electrons in the 2s orbital, right? Okay? So, we've got BE there, 2s, 2s BE, but is it BE2 that we have? No, it's BE2 plus, right? So one of these is not a BE, it's a BE plus, right? Is everybody okay with that? So we'll keep that one as BE, and we'll turn this one to BE plus, right? Because BE plus BE plus equals BE2 plus, are you okay? Okay. So anyways, atomic orbital, atomic orbital, we need to make molecular orbitals, okay? So how do we do that? Well, we're going to make the bonding molecular orbital down here. We call it the, in this case, what do you think we call it? Sigma 2s, yeah. And up here, it's going to be the sigma star 2s. That's the antibody, okay? So now let's decide how many electrons these two berylliums have. So this one in the 2s orbital has two, right? One, two. This one has one, right? Right, one. Why? Because that means it's lost some electron, not positive. So already you guys should be able to predict, does this molecule exist or not? Yeah, it exists. Not a very strong bond, okay? But it's some kind of tenuous bond. We'll go over that. Okay, so let's fill this thing up. So what do we do? Two electrons down here. And then the third one up there, right? Okay, so we have more bonding electrons than we do anti-bonding electrons. So that's kind of a rule of thumb. You can say, okay, that thing exists. But if it asks you, well, what's the bond order? Let's figure that out. Bond order equals one half the bonding electrons minus the anti-bonding electrons. So one half times one is one half. So the bond order is one half here. So it's not even a full single bond, really, okay? But if it asks the next question, does this molecule exist? Well, what did we say? If this is greater than zero, then it exists, right? So does this molecule exist? Do you think you guys can do the 2s-type molecules? Okay, I have another one recorded for you guys. If you can't do them, look at that.