Functional group

Definition

A functional group is a specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule. Functional groups are the sites of reactivity in organic compounds.

5 Must Know Facts For Your Next Test

1. Functional groups determine the properties and reactions of organic molecules.
2. Common functional groups include hydroxyl, carbonyl, carboxyl, amino, and alkyl groups.
3. The presence of a functional group can influence the physical properties such as boiling point, solubility, and melting point.
4. Functional groups can be used to classify organic compounds into different families (e.g., alcohols, aldehydes, ketones).
5. Isomers can have different functional groups leading to different chemical behaviors despite having the same molecular formula.

Review Questions

• What role do functional groups play in determining the properties of an organic molecule?
• Can you name at least three common functional groups and describe their general structure?
• How do functional groups affect the classification of organic compounds?

Related terms

Hydroxyl Group:

A hydroxyl group ($-OH$) consists of an oxygen atom bonded to a hydrogen atom. It is characteristic of alcohols.

Carbonyl Group: A carbonyl group ($C=O$) consists of a carbon atom double-bonded to an oxygen atom. It is found in aldehydes and ketones.

Carboxyl Group:

A carboxyl group ($-COOH$) consists of a carbonyl group bonded to a hydroxyl group. It is characteristic of carboxylic acids.