Basic Concepts of Inorganic Chemistry, 2nd Edition

13

Group 12 (II _B) - Zinc, Cadmium, Mercury

Zinc (Zn), cadmium (Cd) and mercury (Hg) are last d-elements in their periods. Their outer electron configuration is (n — 1)d¹⁰ns². They form +2 ions only (M⁺² ions) which have configuration (n — 1)d¹⁰. As the elements or the ions they form have full filled (n — 1)d orbitals, they are not true transition elements. However, they form a group of their own and are placed with transition metals. There is some similarity to transition metals w.r.t. complex formation especially with NH₃, CN⁻, halide ions and amines.

Electronic configuration

Table 13.1

Mercury is unique. It is the only metal which is liquid ...