 Okay, so let's go over a little kind of rule of thumb video about determining the number of sigma bonds and pi bonds in these different types of bonds. So a single bond would be something like, I don't know, what you find in methane. A double bond might be something like you would find in formaldehyde, because I remember doing formaldehyde last time, to see the double bond there. And the triple bond, I guess we just did a settling. Okay, so what we want to figure out is the number of sigma bonds and the number of pi bonds in each of these particular structures. And we're going to point to one of the bonds that we're looking at, sewing that one. So how many bonds are between carbon and hydrogen there? One, right? So what did I tell you about sigma bonds? The first one made is a sigma bond, okay? So in between carbon and hydrogen there, how many sigma bonds are there? Just one, okay? So in other words, you can say, you have a single bond, you have only a sigma bond. Is that okay? Okay, so how many pi bonds if you want to even go there? Zero. Zero, right? Okay, so let's look at this bond here, this double bond in formaldehyde. So how many sigma bonds are in this double bond? One, right? Why? It's the first one. First one's always a sigma bond. And the second one and third one are always what? Pi bonds, okay? So how many pi bonds does this one have? One. So a double bond is composed of a what and a what thing? Sigma bond or the pi bond? Is everybody okay with that? So let's isolate this bond and look at it. How many sigma bonds? One. So in any bond that you see, how many sigma bonds are there always? One, only. And how many pi bonds would there be in this triple bond? Two. Is everybody okay with that? What is, how about this? What's the bond angle here? 180. What's the hybridization of that carbon? Harden? SPT. What? I see G's and P's and what's going on? So let's try it. SP. Okay, SP. Okay, so what is the bond angle there? What is it? 120. Why is that? 120. What do we measure? Well, you're getting ahead of yourself. So what do we measure? How do we figure out that it's 120? There's three electron groups, right? Three electron groups around. So if it's 120, it's because there's three electron groups around. So what's the hybridization of this carbon? SP2. How did you figure that out? Bond angle. What's the bond angle here? 109.5. Why did people say 90? Because it looks that way, right? But it's drawn, this is, what kind of drawing is this? It's a fluid structure, right? And what drawings show us the angles of bonds? Are they fluid structures? Not under these perspective structures, right? So when you see this, you can't just plop down 90, okay? Because it's not 90, it's 109.5. You know that this is not a two-dimensional molecule. So I guess the last question is, if it were 90, what would be the hybridization? So what's the hybridization here? SP3. It's okay though, it's good. Any questions on this?