Question

Which of the following elements will form white salts and why?

Zinc (Atomic No. 30), Scandium (Atomic No. 21), Nickel (Atomic No. 28) and Vanadium (Atomic No. 23).

Answer 1

Zinc forms Zn²⁺ ions with the configuration [Ar]3d¹⁰, which has a filled d-subshell and no unpaired electrons, so zinc salts are white. Scandium forms Sc³⁺ ions with the configuration [Ar]3d⁰, which also has no unpaired electrons, so scandium salts are white. Nickel and vanadium ions contain unpaired d-electrons; therefore, their salts are coloured.