Question

Which of the following is a stable oxidation state of lanthanides?

• A. +1
• B. +2
• C. +3
• D. +4

Answer 1

The correct option is C +3

The general electronic configuration of lanthanides is :

$4f{}^{1-14}5d{}^{0-1}6s{}^2$

So, there are one electrons of 5d and two electron of 6s available for removal. So, the most common and stable oxidation state of lanthanide is +3.

Occasionally +2 and +4 oxidation states are also obtained due to extra stability of empty, half-filled and fully filled f subshell.