Which oxidation state is most commonly exhibited by the lanthanide elements in their aqueous compounds?

Step-by-step solution

1. Recall that lanthanides have the electronic configuration $[Xe]4f^{n}6s^2$ where n = 0 to 14.
2. In aqueous solution the 6s electrons are readily removed, and the 4f electrons are poorly shielded, making the +3 state stable.
3. Examine experimental data: the majority of lanthanide salts (e.g., chlorides, nitrates) contain the ion $L{n}^{3+}$.
4. Therefore the oxidation state most frequently observed is +3.

Concept tested: common oxidation state of lanthanides

Published 2 September 2026 · How this solution was prepared and checked

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