 In this video we are going to look at the functional groups I introduced in the last one and learn how to name molecules when they have these functional groups in them. So remember the basic rules for naming a molecule. You find a name, the longest continuous carbon chain. You identify and name any groups or substituents that are attached to this chain. And you number the chain so as to give the lowest possible numbers in the name. But what about if we have a functional group in the molecule? How do we indicate that in the name? Well this table shows the functional groups we met in the last lecture. Each of these groups has a different suffix that is added to the molecule's name to indicate that it's there. Alkanes, alkenes and alkynes you already know. For instance you use the ene suffix to indicate that there is a double bond in the molecule. And you use the iron suffix to indicate that there's a triple bond. Halo alkanes don't actually have a suffix. They're always treated as a substituent. So they get added as a prefix to the front of the name. A bit like hydrocarbon substituents like methyl and ethyl. We'll look at examples in a later video. The other groups each have their own suffix. If a molecule has an OH group in it, it's an alcohol. And so the end of the name will be ol. For instance a three carbon chain by itself is propane but with an OH group attached it's called propanol.