Answer 1

i. Condensed electronic configurations of Sc³⁺, Ti⁴⁺, V⁵⁺ are: Sc³⁺: [Ar] 3d⁰ ; Ti⁴⁺: [Ar] 3d⁰ ; V⁵⁺: [Ar] 3d⁰

ii. The ions Sc³⁺, Ti⁴⁺ and V⁵⁺ have completely empty d-orbitals i.e., no unpaired electrons are present. Thus, their salts are colourless, as d-d transitions are not possible.