What are Functional Groups?

A functional group is an atom or a group of atoms that makes a carbon compound or an organic compound reactive and determines its properties. 

Functional groups are atoms within molecules that have distinct properties regardless of the other atoms in the molecule. In organic chemistry, functional groups are the substituent atoms or groups of atoms that are connected to certain molecules. The halo group, alcohol group, aldehyde group, ketone group, carboxylic acid group, alkene group, alkyne group, etc. are some of the most important functional groups in organic chemistry.

Functional Groups if added to hydrocarbons change their functionality and properties. A hydrocarbon is a compound made up of hydrogen and carbon, which can be either saturated or unsaturated. A saturated hydrocarbon is one in which the carbon atoms are joined by only a single bond and an unsaturated hydrocarbon is one in which a double or triple bond between carbon atoms is present. Generally, a saturated hydrocarbon is very less reactive, but when another ‘atom’ or ‘group of atoms’ is attached to it, the resulting molecule becomes highly reactive depending on the attached group. The other ‘atom’ or ‘group of atoms in a carbon compound is called a functional group.