Functional Groups
A functional group sets a molecule's reactions.
About this topic
A functional group is a specific arrangement of atoms in an organic molecule that determines its characteristic reactions. Common groups include hydroxyl (−OH, alcohols), carbonyl (C=O, aldehydes and ketones), carboxyl (−COOH, carboxylic acids), amine (−NH2), ester (−COO−), ether (C−O−C), amide and halides.
Molecules with the same functional group behave similarly, regardless of the size of the carbon chain, which makes organic chemistry predictable. Polar groups such as OH and COOH increase solubility in water and boiling points through hydrogen bonding. Carboxylic acids are weakly acidic, amines are basic, and esters often have sweet fruity smells. Names use suffixes: -ol for alcohols, -al for aldehydes, -one for ketones, -oic acid for acids, -oate for esters.
Example: ethanol (CH3CH2OH) and propanol both react with sodium and can be oxidised, while ethanoic acid and propanoic acid both turn blue litmus red. Amino acids have both an amine and a carboxyl group, joining to build proteins. Aspirin contains an ester and a carboxylic acid; vanilla flavour comes from vanillin with aldehyde, ether and hydroxyl groups.
Students often mix up the names of groups, such as ketone versus aldehyde (position of C=O) or ester versus ether. Learn the structures and suffixes together, and remember that one molecule can have more than one group.
Key ideas
- –OH alcohols
- –COOH carboxylic acids
- –NH₂ amines
Quick check
Use cases: where Functional Groups helps
- Homework: review the key idea behind Functional Groups before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Functional Groups without notes.
- Visual learning: play with the interactive lab to see how Functional Groups changes when you adjust its inputs.
- Teaching a friend: explain Functional Groups in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Functional Groups?
A functional group sets a molecule's reactions.
What will I learn in Functional Groups?
–OH alcohols. –COOH carboxylic acids. –NH₂ amines.
Is Functional Groups part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Functional Groups lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Functional Groups?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.