Question

Diamagnetic Lanthanoid ions are:

• A. Nd$^{3+}$ and Eu$^{3+}$
• B. Nd$^{3+}$ and Ce$^{4+}$
• C. La$^{3+}$ and Ce$^{4+}$
• D. Lu$^{3+}$ and Eu$^{3+}$

Answer 1

Answer: (C)

La$^{3+}$ and Ce$^{4+}$

Answer 2

Step 1. Understand Diamagnetism: Diamagnetic species have all electrons paired, which means the ions should have no unpaired electrons in their electron configuration.

Step 2. Examine Electron Configurations: Ce 4+: [Xe] 4f0 - All electrons are paired, hence diamagnetic. La 3+: [Xe] - Also has no unpaired electrons, hence diamagnetic.

Step 3. Conclusion: La3+ and Ce4+ are both diamagnetic as they lack unpaired electrons.