Question

Explain the following facts, metallic gold has the highest electron affinity energy of any metal outside group VIIA, forms a stable diatomic gas and dissolves in a solution of rubidium metal in liquid ammonia to give a precipitate which is is an insulator in the solid but conducts when molten.

this is for a physical chemistry course so if it could be answered in that context that would be fantastic

Thank You

Answer 1

It is due to the fact that the outer electrons of a gold atom experience particularly large relativistic effects which lead to a distinct contration of the 6s orbital and a weaker contraction of the 6p orbital ( = reduction of the energies of these levels) and an expansion of the 5d orbital (= increase in the energies of these levels). This relativistic effect causes the metallic gold to have highest electron affinity energy of any metal outside group VIIA.