Organic Chemistry — Key Functional Groups

Functional groups determine the chemical behavior of organic molecules.

Must-know functional groups:

Alkane — C−C single bonds; nonpolar; low reactivity

Alkene — C=C double bond; electrophilic addition reactions

Alkyne — C≡C triple bond

Alcohol — −OH; hydrogen bonding; can be oxidized

Aldehyde — −CHO; easily oxidized to carboxylic acid

Ketone — C=O (not at end); harder to oxidize

Carboxylic acid — −COOH; acidic (pKa ~5)

Ester — −COO−; formed from acid + alcohol

Amide — −CONH₂; found in peptide bonds

Amine — −NH₂; basic

Ether — R−O−R; relatively inert

Thiol — −SH; forms disulfide bonds

Phosphate — −OPO₄; in ATP and DNA backbone

Oxidation states: Aldehyde → carboxylic acid (oxidation). Ketone resistant to oxidation. Tollens' reagent distinguishes aldehyde (positive) from ketone (negative).

Reference:

Wikipedia: Functional Group

https://en.wikipedia.org/wiki/Functional_group