Naming Organic Compounds (Edexcel IGCSE Chemistry: Double Science)

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

 

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 isomers 

Isomers can be distinguished by following the naming rules