Question

The colour of transition metal compound is due to

• A. complete ns subshell
• B. small size metal ions
• C. incomplete $(n-1)\,d$ subshell
• D. absorption of light in $UV$ region

Answer 1

Answer: (C)

incomplete $(n-1)\,d$ subshell

Answer 2

Most of the compounds of transition metals are coloured in solid state or solution. This is due to their incomplete $(n-1)$ $d-$ subshell. Their colour arises from the excitation of electron from d-orbitals of lower energy to $d-$ orbitals of higher energy (i.e., $d-d$ transition).