International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What type of bond connects the carbon atoms in alkanes?

1. Double bonds

2. Single bonds

3. Ionic bonds

4. Coordinate bonds

The correct answer is: Single bonds

In alkanes, the type of bond that connects the carbon atoms is a single bond. Alkanes are saturated hydrocarbons, which means they contain only single bonds between carbon atoms and are fully saturated with hydrogen atoms. Each carbon atom in an alkane forms four bonds, usually with other carbon atoms or hydrogen atoms. The presence of single bonds signifies that the carbon atoms can freely rotate around the bond axis, contributing to the flexibility of the alkane chain. This is in contrast to other types of bonds, such as double bonds, which restrict rotation due to their planar nature, or ionic bonds, which occur between charged particles, and coordinate bonds, which involve a shared pair of electrons where one atom provides both electrons. In the case of alkanes, the simple, straightforward structure based on single bonds is what defines their saturated nature and stability.