Which of the following oxidation states is the most common among the lanthanoids?
- 4
- 2
- 5
- 3
Answer
(4) 3
Solution
As per NCERT, all lanthanoids show +3 oxidation state (formation of Ln3+ by loss of two 6s and one 4f/5d electron), which is the most common and stable one.
+2 (e.g. Eu, Yb) and +4 (e.g. Ce) are shown by only a few elements, usually to attain f0, f7 or f14 configurations.
Answer: (4)