Most transition metals:(I) Form sets of compounds which display different oxidation states of the metal.
(II) form coloured ion in solution
(III)burn vigorously in oxygen
(IV) form complex compound of these

Options

A. I,II,III are correct
B. II,III,IV are correct
C. I,II are correct
D. all the correct

Answer

C

Explanation

(I) show variable oxidaton state as `(n-1)` and ns orbitals have nearly the same energy and ,thus ns as well `(n1-)` orbital electrons can be lost giving variable oxidaton state.
(II) Colour of the compound may be attributed to the incomplete `(n-1)` d subshell which may involved in d-d transition of electrons in presence of ligands.
(III) They have low volatility because of high enthalpies of atomization on account of strong metallic bonding.