Shapes of Organic Molecules; σ & π Bonds (Cambridge (CIE) A Level Chemistry): Revision Note

Straight, Branched & Cyclic Molecules

• Straight, branched and cyclic organic molecules are also called aliphatic compounds as long as they do not contain a benzene ring

Straight-chain

• Straight-chain organic molecules are those in which the carbon atoms are connected to each other in one continuous chain

 A straight-chain organic molecule

Pentane is a straight-chain organic molecule as the carbon atoms are connected in a straight line

Branched

• Branched organic molecules have side groups attached to the main chain of carbon atoms

A branched organic molecule

2-methylbutane is a branched organic molecule as the main chain (consisting of 4 carbon atoms) has a methyl branch

Cyclic

• Cyclic organic molecules are those in which the carbon atoms are connected to each other in a ring shape

A cyclic organic molecule

Cyclopentane is a cyclic organic molecule as the carbons are attached to each other in a ring structure