 So let's try, let's recall from last time how to hybridize our atomic orbitals into molecular orbitals for the compound CH4. And specifically, we're talking about the carbon. Because if we think about carbon, we recall that it's condensed electron configurations is helium 2S2 2V2. Right? So if we think about building a molecular orbital diagram, atomic orbital diagram, we'll have the 2S and the 2P orbitals here. And so everybody's okay with that, right? Everybody's okay with that. And when we fill it in, we're going to fill it in. One, two, and then one, two like that. But recall when we're talking about how the P orbitals lie, right? So they lie on these three axes like that. That's all three of them together. And if you notice, right, these axes of course are, what's the angle between those orbitals on this axis? 90 degrees, right? So we were going to measure the angle between the Z and the Y axis there. So it would be 90 degrees. So we know for a fact that the bond angles in methane are what? Do you guys recall? 109.5. 109.5, right? Okay. So if they were bonding with atomic orbitals, they would be 90 degrees, not 109.5. Also we know that you have to have two electrons in an orbital to make a bond, okay? So in order for carbon to make a bond without rehybridizing, we're getting to the rehybridization part, right? We would expect it to only be able to make two bonds and they would be 90 degrees from each other or 180 or whatever. And that's not going to happen because of course we know that. So what does happen? You guys recall? So you can say rehybridize or hybridize or mix or whatever you like. So what do we mix? We're going to, we want to make four bonds, right? And we've got four electrons. So we're going to have to mix how many orbitals? Four, right? So we mix all four of these. So when we mix one S and three P's, how many, or what type of orbitals do we get out of? SP3. You guys can talk louder if you want to. And how many of them do we get? Four. Four. Why? Because we put four in, so we get four out, right? They're of equal energy value, so the electrons are going to fill as such, okay? Is everybody okay with that? Any problems with what we've done? Okay, so when we're talking about the bonding in methane, right? So remember, SP3 orbitals have a little bit of S character and a lot of P character, so they look kind of like P's, okay? But their directionality has changed. Remember, this went from 90 degrees to 109.5. So let's kind of draw that carbon, or let's just draw one of them, because if we draw all of them, they'll get kind of, but anyways, it'll be hard to tell. Okay, so this is one of the SP3 orbitals in carbon, and it's got its one electron, okay? So this will happen four times, so we'll say this is an SP3 orbital. What's going to happen is the hydrogen atom, right? So this is the hydrogen atom with its 1s orbital. It's going to have its 1s orbital and kind of stick on to that SP3. But that's going to happen three times. It's going to fill up. Is there any problem with that? Question? Concerns? Okay, good job, guys. We'll do a few more of those. We'll do a review session on Friday and we'll do the rest of the ones that we did before.