Organic compounds are divided into four categories:
(1) Aliphatic compounds- alkanes (H3C-CH3), alkenes (H2C=CH2) and alkynes (HC≡CH). Compounds containing open chain of atoms.
(2) Alicyclic compounds- cyclopropane (C3H6).
(3) Aromatic compounds- benzene (C6H6), toluene (C6H5CH3)
(4) Heterocyclic compounds- pyridine (C5H5N). Cyclic compounds in which the ring contains elements other than carbon.
Catagories (1), (2) and (3) are known as hydrocarbon (compounds of carbon and hydrogen).
Functional Groups
Ø A functional group is the reactive part of an organic molecule.
Ø It serves to classify organic compounds into classes/families.
Ø It serves as a basis for nomenclature (naming) of organic compounds.
Alkenes (-C=C-), alkynes (-C≡C-), alcohols (-OH), ethers (-O-), aldehydes (-CHO), ketones (-CO), acids (-COOH), esters (-CO-O-), amines (-NH2), halides (-F, -Cl, -Br, -I) etc.