Lesson eLearning

The oxidation state most commonly exhibited by lanthanide ions in aqueous solutions is:

medium MCQ 1 mark Class 12 · Chemistry · d- and f-Block Elements
  1. A) +2
  2. B) +3
  3. C) +4
  4. D) +5
Answer
B) +3

The correct answer is B) +3 — Therefore the predominant oxidation state observed in aqueous solutions is +3.

Step-by-step solution

  1. Recall that lanthanides have the general electron configuration .
  2. Loss of the two 6s electrons and one 4f electron gives a stable oxidation state for the majority of lanthanides.
  3. Recognise that the +2 state is only stable for the heavier lanthanides (Yb, Lu) and +4 for a few early members (Ce, Pr).
  4. Therefore the predominant oxidation state observed in aqueous solutions is +3.
Common mistake: Choosing +2 because it appears for the heavier lanthanides

Concept tested: Common oxidation state of lanthanides

Published · How this solution was prepared and checked

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