Functional Groups
Chemistry: Cambridge International GCSE Supplement, topic 11.1.3
Functional Groups
Functional groups are atoms or groups of atoms in molecules that give homologous series their chemical properties.
What is a functional group?
- A functional group is an atom or group of atoms in an organic molecule.
- The functional group controls the chemical properties of the molecule.
- Molecules with the same functional group belong to a homologous series.
- Functional groups cause similar reactions in compounds within a series.
Importance of functional groups
- Functional groups help chemists predict how molecules will react.
- Identifying functional groups helps name organic compounds correctly.
- Functional groups allow classification of organic compounds into families.
- Different functional groups make molecules behave differently in experiments.
Examples of common functional groups
- Alcohol group: –OH (hydroxyl group), found in alcohols.
- Carboxylic acid group: –COOH, found in carboxylic acids.
- Alkene group: –C=C–, found in alkenes (unsaturated hydrocarbons).
- Halogen group: –X (where X = Cl, Br, I), found in halogenoalkanes.
Summary and applications
- Functional groups define the chemical behaviour of organic substances.
- Chemists use functional groups to predict reactions and properties.
- Knowledge of functional groups is essential for understanding organic chemistry.
- Functional groups link structure and function in organic compounds.
Test yourself on Functional Groups
Molecules that belong to the same homologous series share what characteristic?
Which of the following is the functional group for an alcohol?