The reactive doorknobs
A long carbon molecule is mostly a quiet hallway, but a functional group is like a doorknob — the specific spot where reactions actually happen. Spotting the -OH or -COOH tells a chemist how the whole molecule will behave.
Where the chemistry happens
A functional group is a specific cluster of atoms that gives a molecule characteristic reactions. The carbon skeleton is the frame; functional groups are the reactive handles.
- Hydroxyl (–OH) — defines alcohols
- Carbonyl (C=O) — found in aldehydes and ketones
- Carboxyl (–COOH) — defines carboxylic acids
- Amino (–NH₂) — defines amines
Lab · Name the group
- Look at ethanol: CH₃CH₂–OH.
- Find the cluster that isn't just carbon and hydrogen.
- Identify which family that group makes it.
What you should see: The –OH (hydroxyl) group makes ethanol an alcohol.