Answer: d-d electron transitions absorbing visible light.
- A d-d electron transitions absorbing visible light
- B Their characteristically high melting points compared to main-group salts
- C Their predominantly ionic character in the solid lattice
- D Their general paramagnetic or ferromagnetic behaviour
Correct answer: A. d-d electron transitions absorbing visible light
Explanation: Partially filled d orbitals allow d-d electronic transitions; the absorbed wavelength corresponds to visible light, producing colour.
Aqueous solutions of transition metal ions show characteristic colours caused by electrons absorbing visible light to jump between split d-orbitals; the exact colour depends on the metal, its oxidation state, and surrounding ligands.
Concept context
Transition metals (d-block) and lanthanides/actinides (f-block). Known for coloured compounds, variable oxidation states, complex formation, and catalytic properties. Frequently tested in JEE and NEET.