Which of the following cations in their oxidation states forms colored compounds ?

Step-by-step solution

The electronic configurations of the given cations are: Sc ³⁺ ( Z=21 ): [ Ar ] 3d^0 Ti ⁴⁺ ( Z=22 ): [ Ar ] 3d^0 Cu ⁺ ( Z=29 ): [ Ar ] 3d¹⁰ V ³⁺ ( Z=23 ): [ Ar ] 3d^2 Cations with d^0 or d¹⁰ configurations do not have unpaired electrons for d-d transitions and are generally colorless. V ³⁺ has two unpaired electrons in its d -orbital, which allows d-d transitions, making its compounds colored. Answer: V ³⁺