Simple hydrocarbons are named based on a few straightforward rules. The first part of the name - the prefix - is determined by the number of carbon atoms in the longest carbon chain. The second part of the name - the suffix - is determined by whether double or triple bonds are present. A visual representation of these principles can be seen in Figure 1.

Examples of saturated and unsaturated hydrocarbons. A saturated hydrocarbon is called an alkane and they contain carbon carbon single bonds. Butane, C H 3, C H 2, C H 2, C H 3, is an alkane. There are two types of unsaturated hydrocarbons, alkenes, and alkynes. An alkene contains a carbon carbon double bond. Ethene, C H 2, C H 2, is an alkene. An alkyne contains a carbon carbon triple bond. Propyne, C H, C, C H 3, is an alkyne.

Figure 1. Overview of the nomenclature principles of simple hydrocarbons.

If more than one location is possible for a double or triple bond, a number is added to indicate its placement on the carbon chain, always counting from one end of the chain and giving the carbon the lowest number possible. Check out how side groups are numbered here.