(i) Name the body which approves the nomenclature of elements and compounds. (ii) The symbol of sodium is written as Na and not as S. Give reason. (iii) Name one element which forms diatomic and one which forms tetraatomic molecules

(i) International Union of Pure and Applied Chemistry.
(ii) The symbol of Na (sodium) is derived from its Latin name Natrium.
(iii) (a) Element forming Diatomic molecule - H^O2, N2 (only one).
(b) Element forming Tetratomic molecule - P4.