Naming organic compounds
Names of compounds
- The names of organic compounds have two parts: the prefix or stem and the end part (or suffix)
- The prefix tells you how many carbon atoms are present in the longest continuous chain in the compound
- The suffix tells you what functional group is on the compound
Examples of naming organic molecules
First part of name | Second part of name | |||
Name | Number of carbon atoms | Name | Functional group | Family |
Meth... | 1 | ...ane | None | Alkane |
Eth... | 2 | ...ene | C=C bond | Alkene |
Prop... | 3 | ...anol | R-OH | Alcohol |
But... | 4 | ...anoic acid | R-C=O-OH | Carboxylic acid |
Pent... | 5 | ....amine | R-NH2 | Amine |
Hex... | 6 | ...yl ...anoate | R-C=O-O-R | Ester |
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Further rules for naming compounds
- When there is more than one carbon atom where a functional group can be located it is important to distinguish exactly which carbon the functional group is on
- Each carbon is numbered and these numbers are used to describe where the functional group is
- When 2 functional groups are present di- is used as a prefix to the second part of the name
Naming isomersĀ
Isomers can be distinguished by following the naming rules
Examiner Tip
You may not be asked to name branched chain organic compounds but you will come across them. It is useful to know that the numbers in the names of these compounds refer to the position of the side chains with respect to the main chain.