| Functional Group | Name | IUPAC Suffix | IUPAC Prefix | SMILES Example | Electronic Effect | Hybridization of Key Atom |
|---|---|---|---|---|---|---|
| -OH | Hydroxyl | -ol | hydroxy- | CCO (ethanol) | -I, +M | O: sp3 |
| -CHO | Aldehyde | -al | oxo-/formyl- | CC=O (ethanal) | -I, -M | C(CHO): sp2 |
| >C=O | Ketone | -one | oxo- | CC(=O)C (propanone) | -I, -M | C(C=O): sp2 |
| -COOH | Carboxyl | -oic acid | carboxy- | CC(=O)O (ethanoic acid) | -I, -M (strongest) | C(COOH): sp2 |
| -NH2 | Amino | -amine | amino- | CN (methylamine) | -I, +M | N: sp3 |
| -NO2 | Nitro | — | nitro- | C[N+](=O)[O-] | -I, -M | N: sp2 |
| -X (Cl, Br, F) | Halide | — | halo- | CCl (chloromethane) | -I, +M(weak in aromatic) | X: varies |
| -CN | Nitrile | -nitrile | cyano- | CC#N (ethanenitrile) | -I, -M | C(CN): sp |
| -OR | Ether | — | alkoxy- | COC (dimethyl ether) | -I, +M | O: sp3 |
NEET Priority: Know -I vs -M vs +M vs +I for each group. The dual character of -OH, -NH2, and halogens (+M but -I) is a perennial NEET trap.