 In this video we're going to look more carefully at the issue of naming molecules and learn to name some molecules that are somewhat more complex. The formal word for naming is nomenclature. So the name of an organic molecule generally consists of three parts. The central or parent part of the name is the part that indicates how many carbons are in the main chain of the molecule. This is the meeth, eth, probe, butte part of the name that you've seen in the alkanes and so on. The suffix of the name tells you about the family of molecules that it belongs to. The suffix an indicates the molecule is an alkane, which tells you it has all single bonds. The suffix ion would tell you that it belongs to the alkynes and that there must be a triple bond somewhere in the molecule. The prefix of the name is where you indicate more complex parts of the molecule. We've already encountered cyclohexane for instance. Cyclo is the prefix for this molecule. It tells you that it's in the shape of a ring. Hex tells you that there are six carbons in the molecule. And ane tells you that the bonds are all single. So I've just quickly stuck this slide in here to revise the names of the alkanes, in particular those word roots that tell you how many carbons are there. You should know these off by heart by now. So in order to help with nomenclature, the International Union of Pure and Applied Chemists, IUPAC, has come up with a list of rules. And I've summarised the basic ones here and we're going to work through them.