Answer: Mn2+.
- A Ti3+
- B Mn2+
- C Cr3+
- D V3+
Correct answer: B. Mn2+
Explanation: Mn2+ is d5 with 5 unpaired electrons (5.92 BM), more than Ti3+ (d1), V3+ (d2) or Cr3+ (d3).
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.