Given below are two statements:
Statement I: The number of pairs among [Ti⁴⁺, V²⁺], [V²⁺, Mn²⁺], [Mn²⁺, Fe³⁺] and [V²⁺, Cr²⁺] in which both ions are coloured is 3.
Statement II: The number of pairs among [La³⁺, Yb²⁺], [Lu³⁺, Ce⁴⁺] and [Ac³⁺, Lr³⁺] ions in which both are diamagnetic is 3.
In the light of the above statements, choose the correct from the options given below:
Solution
Solution
Statement I. An ion is coloured when it has partly filled d orbitals.
- Ti⁴⁺ is 3d⁰ (colourless); V²⁺ 3d³, Cr²⁺ 3d⁴, Mn²⁺ 3d⁵ and Fe³⁺ 3d⁵ are all coloured.
- Only [Ti⁴⁺, V²⁺] fails, so 3 pairs have both ions coloured. Correct.
Statement II. An ion is diamagnetic when its f (and d) subshells are empty or full.
- La³⁺ 4f⁰, Yb²⁺ 4f¹⁴, Lu³⁺ 4f¹⁴, Ce⁴⁺ 4f⁰, Ac³⁺ 5f⁰, Lr³⁺ 5f¹⁴: all diamagnetic.
- All 3 pairs qualify. Correct.
Answer: both statements are correct.
Answer checked against the official answer key. The solution is our own working.