Q12 / 150 · MHT CET 2025 (21 Apr Shift 1) · Chemistry
Which from following cations will form most stable complex with same ligand?
- Correct answerA$\mathrm{Cu}^{2+}$
- B$\mathrm{Co}^{2+}$
- C$\mathrm{Mn}^{2+}$
- D$\mathrm{Fe}^{2+}$
Solution
The stability of coordination complexes formed by divalent transition metal ions follows the Irving-Williams series: $Mn^{2+} < Fe^{2+} < Co^{2+} < Ni^{2+} < Cu^{2+} > Zn^{2+}$. This trend results from decreasing ionic radii and increasing effective nuclear charge across the period, enhanced by crystal field stabilization effects.
Among the given ions, $Cu^{2+}$ exhibits the highest stability due to maximum crystal field stabilization energy among first-row transition metals and Jahn-Teller distortion effects.
Final Answer: $\boxed{A}$
Hence, the correct answer is option: 'A'.