Hey, guys, let's take a look at the question that was left for us on the bottom of the page. So here, ask us based on your knowledge of chemical structures, draw the three ice MERS of painting. So pen tain is just five carbons and it's a now cane. So the simplest when we can draw is just ch three connected to ch two connected the ch two connected to ch two connected to ch three. Now how do I quickly draw the other two I summers? What I'm gonna do here is I'm going toe hold this metal group still don't move it and realize here what I have is I have a four carbon chain. So if you think about it, what do I do? So that methyl group that I'm holding still just imagine that's a group that that four carbon chain is connected to So that four carbon chain that I just drew is beautiful and realize that if you could draw beautiful that you can draw sect beautiful that you can draw isil beautiful. You can draw ter beautiful because they all have four carbons in them And not thinking to answering this question quickly by knowing about each of those groups. So here, suck beautiful. The bond would be on the second carbon, the second Dairy Carbon if you wanted to draw ice so beautiful. And then if you want to draw terp Udal, Right. So all we're doing is we're gonna change that chain into these other scenarios. So we're not messing with this metal group. So here, let me just take them at the group in, bring it down and connected to this secondary carbon here and see what that gives me. So this is a different way I can draw the compound. What else could I dio? All right, I could now try to draw this right here. I so beautiful. So keep that metal group. Then what you're gonna do is you're gonna draw connected to that right there and then here. Oops. Draw that method group and draw this terp beautiful around it. All right, so we're gonna say here that we have to draw the three ice Mursal. This is icing. Or one will say that this is too. And in these actually are the same. How do we know that? The same. Where you going to say here is We're gonna say the longest carbon chain we have is this right here When we're count, When we're counting a carbon chain trying to figure out the longest carbon chain, you just count down the chain and see what's the longest it can be. So the longest it could be us for this month. A group never got counted, so it's a substitue int and I'll keel group substitue int later on. When we do, naming this will become much more clear. So we want to count from the end closest to that substitute. So one to three and four. So we have a four carbon chain with a group branching off carbon number two, Remember? And Al Kiel. Substitution is just a branching group. It's not part of the longest chain. It's branching off of one of the carbons on the longest chain. Now, if we take a look at this one down here, the longest carbon chain again is four carbons. And here that would mean that this metal group appears a branching group. So count from the end closest to that branching group. So this is one to three and four, so in both the longest carbon chain is four carbons, and there's a branching group off of carbon number two. So there are identical, so you don't count both of them because they're the same thing. Just count one of them. So this would be my first I summer. This would be a second I summer, and this will be my third eye summer. This is just a repeated version of it. So that's how we approach Al Kiel groups. Why they're so important. They're important because they're gonna help us with naming later on. But they're also important because they give us a quick method for getting all the structural ice MERS based on just the al que name or formula. We just quickly drew all three of these without really having to think very much. It all boils down to remembering what they're called again. I'm gonna say this a lot. When you get to organic, you're gonna Seymour complicated types of questions like this. Ah, question like this is typical in the first few weeks of or go, but just realize it's gonna get more and more complex than this. But again, it all hinges on you remembering the fundamentals that we're learning now, knowing these groups speeds up the amount of time that you need in order to draw all the ice summers.