MCQ
Which of the following oxidation state is common for all lanthanoids?
- A$+2$
- ✓$+3$
- C$+4$
- D$+5$
✓
Answer
Correct option: B.
$+3$
In the lanthanoids$, \text{La(II)}$ and $\text{Ln(III)}$ compounds are predominant species. However, occasionally $+2$ and $+4$ ions in solution or in solid compounds are also obtained. This irregularity $($as in ionisation enthalpies$)$ arises mainly from the extra stability of empty, half$-$filled or filled $f$ subshell.
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