What is a functional group?
A small atomic 'badge' that decides how the molecule reacts.
Organic chemistry is a vast subject — there are tens of millions of known compounds. To organise them, chemists look at the FUNCTIONAL GROUP: a small arrangement of atoms (or a specific bond pattern) that gives the molecule its characteristic reactions.
If two molecules have the same functional group, they react in similar ways — regardless of how long the carbon chain is. This is the basis for homologous series (families of organic compounds).
The main MYP functional groups:
| Group | Suffix | Family | Example |
|---|---|---|---|
| –C–C– (single bonds only) | -ane | Alkane | propane (CH₃CH₂CH₃) |
| C=C (double bond) | -ene | Alkene | propene (CH₃CH=CH₂) |
| –OH | -ol | Alcohol | propan-1-ol (CH₃CH₂CH₂OH) |
| –COOH | -oic acid | Carboxylic acid | propanoic acid (CH₃CH₂COOH) |
The functional group is the "active" part. The rest of the molecule (the unreactive carbon chain) is sometimes called the "spectator" part.
- Functional group = reactive part of the molecule.
- Same group → similar chemistry across the family.
- Four main MYP groups: single C-C, C=C, –OH, –COOH.