 Okay, so now let's go back to structural isomers, talking about structural isomers. So, instead of, okay, so remember C4H10 we talked about, that's a saturated hydrocarbon, okay? So, if it's something lower than the CNH2N plus two in agents, right? If it's something like C4H8, we know it's gonna be not a saturated hydrocarbon, okay? So, let's go ahead and erase everything else. If you've got this formula here, see what would be CNH2N, okay? That means you've either got one ring in your structure or one double bond, okay? One ring or one double bond. This is a saturated hydrocarbon, we'll erase all of them. So, C4HA, we should be looking for rings and double bonds, okay? So, let's draw some molecules in a ring that have four carbons. Remember that agents all have to be on the outside still, right? Because they can only make the one bond. So, it's gonna be in a ring with something like that. So, is there any other types of rings that you can make with four carbon atoms? Let's think of one. One that has, doesn't necessarily have to have four all in the ring, right? You can have three in the ring and one outside of the ring, like that, okay? So, let's go ahead and fill in our hydrogen so we don't get confused. Let's draw the bottom line form of this. What does it look like? What about this thing? How many hydrogens are there? Could you think of another one? Something like that, maybe? Something weird like that? That doesn't work though, right? There's only six hydrogens, okay? But what else did we say? It's not only a ring, but what? A double bond, right? So, could we put a double bond? We've got four carbons, right? So, it can't be a ring and a double bond, okay? It's gonna be one or the other. So, we could put carbon, carbon, double bond, carbon, carbon, like that, would that work? Could we do it a different way? Yeah, how else could we do? Carbon, double bond, carbon, carbon, carbon. Okay, let's just draw the hydrogen in in both of these structures. Hydrogens, two hydrogens, one hydrogen, one hydrogen, three hydrogens, right? And all together, that's eight here. This looks weird, because usually, you wanna do it at a 120-degree bond angle. We'll talk about that later. Is the same molecule? Why? Because you gotta break them on and make them off, right? You definitely have to make that bond there, if they're gonna be the same molecule, right? And that's what we're gonna do. So, let's draw the bond line form to these things. So, this one, remember Charlie Brown. So, one, two, three, four. This thing's called one-butene, one-butene. Whenever that's, whenever, so, we'll write one. Whenever you see this EME, that means you've got an alkene, which is a functional group that's developed on between two carbon atoms. So, functional groups I talked about last time is being around heterologues. They're also around multiple bonds in carbon-carbon models, or carbon-carbon ones. This one, what do you think the name of this one's called? Two-butene. Two-butene, yeah, it's two-butene. Now, how'd you figure that out? It's because you did this. One, two, three, four, like that, okay? Like, double bonds on the first carbon, okay? It goes in between the first carbon. First and second carbon. Here, so, here we go. Why didn't I do it one, two, three, what do you call this, three-butene? It's because the double bond carbon takes precedence over the other, okay? This guy here is called two-butene. Why? One, two, three, four, right? So, it's in between the second and third carbon. So, it's called two-butene. Hey, let's draw the bond line form of this. Remember Charlie Brown, like that, okay? Does it matter if it's on the top? Double bonds are on the bottom or on the top? I don't know what that question means. I did it on the top, and you did it on the bottom, so it doesn't matter. I don't know what you're saying, I'm sorry. Do you have to show me your thing? Your line, do you have it on? Yes, show it. Can you have it on me, but I can't get it because I can't understand it. Yeah, so, it does not matter, no, it doesn't matter. So, the question was this, can I draw it like that? Or can I draw it like that? They're both the same molecule, okay? Or, you can draw it. Like how I drew it, like that, okay? So, it's all the same thing, okay? Two-butene, okay? So, we're going to go more into this structure in a second, okay? So, notice they all have the same formula, C4H8, okay? So, I can't think of any more. The other thing is, is why didn't we say, let's do three of you, right, like this one? Why didn't we do that one? Why didn't I think about it? It's the same as this one. Why? Because I turned it around and it's the same thing. So, these are just conformational isomers of each other. Okay, does that make sense? That's just like me going like this. It's the same thing. It's a conformational isomer of each other, you know? They're really okay with that. So, any other questions? Okay, cool.