 In this video we'll look at some examples of how to name haloalkane molecules. Haloalkanes are also known as alkylhalides or halogenoalkanes. Haloalkanes are right down the bottom of our list of functional groups, and in fact they don't really count as a functional group as such, but rather as substituents, a bit like alcohol branches. Let's look at some examples. Haloalkanes are so-called because they have a halogen atom attached to them. The halogens, remember, are the group 7 elements, fluorine, chlorine, bromine and iodine. When they're attached as a substituent to a hydrocarbon, they are named as fluorocluorobromo and iodo. Let's try naming this first one. The longest carbon chain here is obvious. It's pentane. So next we'll look at the substituents. For no alkyl groups, only the two chlorine atoms. So we number the chain in order to give the chlorines the lowest possible number. That will mean numbering from the right. So we will have 2-chloro and 3-chloro. We can indicate that we have two of the same kind of substituent by using dye. So instead of 2-chloro and 3-chloro, we call it 2-3-dichloro. And then we put that all together and we have 2-3-dichloropentane. Let's try the next one. Here the main chain is a cycloalkane. It has six carbons. That's why it looks like a hexagon. So it's cyclohexane. Now when you number the carbons in a ring, you can call any carbon you like number one. You're just guided by the need to make the numbers in the final name low. So we have two options. We can start here and make the carbon that the bromine is attached to number one, and then the fluorine one would be number two. Or we could do it the other way round, making it 1-chloro and 2-bromo. So how do we choose? Well, we have guidelines here. If you have more than one type of halogen and there's no way of deciding which should get the higher priority, you do it by atomic mass. The heavier the halogen atom, the higher its priority. So here bromine is a heavier atom than fluorine. So we're going to go with our first numbering option, which will give us 1-bromo and 2-fluoro. Now when we're putting the name together, we have to fall back on the rule that we already know that substituents in the name should be ordered alphabetically. So bromo will come before fluoro in the name. So the complete name is 1-bromo, 2-fluoro, cyclohexane. Okay, last example. Longest chain, 7 carbons. And there is a double bond, so we begin by calling it heptene. Next we'll number the chain. Here we've got a functional group that's going to change the suffix of the name, the alkene. So we have to number the chain so that the alkene gets the lowest possible number. That means numbering from the right, so it will be hept 2-ene. Continuing the number, we find that the two iodine atoms are joined onto carbon number 6. So our final name will be 6-6 diiodohept 2-ene.