There's a methyl group on the number 2 carbon - therefore 2-methylpentane.

Are there any carbon-carbon double bonds? No - therefore pentane.

Don't assume that you have necessarily drawn that chain horizontally.

Count the longest chain of carbons that you can find.

That's exactly the same as the first one, except that it has been flipped over.įinally, all you have to do is to put in the correct number of hydrogen atoms on each carbon so that each carbon is forming four bonds. Put a methyl group on the number 2 carbon atom:ĭoes it matter which end you start counting from? No - if you counted from the other end, you would draw the next structure. Start decoding the name from the bit that counts the number of carbon atoms in the longest chain - pent counts 5 carbons.Īre there any carbon-carbon double bonds? No - an tells you there aren't any. Come back to them as they arise during the natural flow of your course.

Just go as far as the compounds you are interested in at the moment and ignore the rest. Don't try to read all these pages in one go. In the early stages of an organic chemistry course people frequently get confused and daunted by the names because they try to do too much at once. In the process you will also pick up tips about how to produce names yourself.

So, we're going to look mainly at how you decode names and turn them into formulae. However, you might only be asked to write a name for a given formula once in a whole exam - in which case you only risk 1 mark. In an exam, if you can't write a formula for a given compound, you aren't going to know what the examiner is talking about and could lose lots of marks. The first of these is more important (and also easier!) than the second. You need to be able to name a compound from its given formula.You need to be able to translate the name of an organic compound into its structural formula.There are two skills you have to develop in this area: It covers alkanes, cycloalkanes, alkenes, simple compounds containing halogens, alcohols, aldehydes and ketones.

This page explains how to write the formula for an organic compound given its name - and vice versa.

Khan academy organic chemistry