What is it?
Chain isomers have the same molecular formula, but the way their carbon atoms are joined together differs from isomer to isomer. Alkane molecules with four or more carbon atoms have chain isomers. In these isomers, the carbon atoms are bonded together in different ways to produce branches.
What is here?
You can see models of the three chain isomers of pentane, C5H12. You can also see the structural and displayed formulae for these alkanes.
Pentane is the unbranched "straight chain" isomer of C5H12. The other two isomers are branched:
- 2-methylbutane has one branch
- 2,2-dimethylpropane has two branches.
In each case, the branch contains one carbon atom and is a methyl group, —CH3.