In organic chemistry, what is a functional group?

A functional group refers to a specific group of atoms within a molecule that determine the chemical properties and characteristic reactions of that compound. Functional groups play a crucial role in chemistry because they define the reactivity and behavior of organic molecules. For example, the presence of hydroxyl (-OH) indicates that the compound is an alcohol, and it will exhibit properties distinct from those of hydrocarbons or aldehydes.

Understanding functional groups is essential in organic chemistry as they serve as the basis for classifying compounds and predicting their chemical reactions. Identifying the functional groups within a molecule allows chemists to infer how it will react under various conditions, making functional groups pivotal for the study and application of organic chemistry.