IUPAC Nomenclature of Straight Chain Hydrocarbons

The names of straight chain hydrocarbons consist of two parts. The first one is word root and second one is suffix.

Word Root

The word root designates the number of carbon atoms in the chain. Special word roots (Meth-, Eth-, Prop-, But-) are used for chains containing one to four carbon atoms but for chains of five and more carbon atoms, Greek number roots such as Pent-, Hex- are used.

Carbon Atoms	Word Root
1	Meth-
2	Eth-
3	Prop-
4	But-
5	Pent-
6	Hex-
7	Hept-
8	Oct-
9	Non-
10	Dec-

The general word root for any carbon chain is alk.

Suffix

In order to write the IUPAC name, a suffix is added to the word root to indicate saturation or unsaturation in the hydrocarbons.

Compound	Suffix	General Name
Saturated	-ane	Alkane
Unsaturated (>C=C<)	-ene	Alkene
Unsaturated (–C≡C–)	-yne	Alkyne