Explain, most of the transition metal compounds are remarkably coloured.
Answers
Answer:
The colour of the transition metal ion is due to the d- d transition. The amount of energy required to excite some of the electrons to higher energy states within the same d-sub shell corresponds to the energy of certain colour of visible light.
Transition metal ions generally possess one or more unpaired electrons. When visible light falls on a transition metal compound or ion, the unpaired electrons present in the lower energe d-orbital get promoted to high energy d-orbitals, called d-d transition, due to the absorption of visible light. Since, the energy involved in d-d transition is quantised, only a definite wavelength gets absorbed, remaining wavelengths present in the visible region got transmitted. Therefore, transmitted light shows some colour complementary to the absorbed colour.