Question:
Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.
Solution:
(i) Vanadate, $\mathrm{VO}_{3}^{-}$
Oxidation state of V is + 5.
(ii) Chromate, $\mathrm{CrO}_{4}^{2-}$
Oxidation state of Cr is + 6.
(iii) Permanganate, $\mathrm{MnO}_{4}^{-}$
Oxidation state of Mn is + 7.