Question

The most common oxidation state for all lanthanoids is:

• A. \( +5 \)
• B. \( +2 \)
• C. \( +3 \)
• D. \( +4 \)

Hint:

Lanthanoids mostly form trivalent ions (\( +3 \)), which is a key feature of their chemistry.

Answer 1

The Correct Option is C

Step 1: Lanthanoids belong to the f-block elements, specifically the 4f series.
They are characterized by the filling of the 4f orbitals.
Step 2: The most stable and common oxidation state for almost all lanthanoids is \( +3 \).
This is due to the stable removal of two 6s electrons and one 5d or 4f electron.
Step 3: Some lanthanoids can also show \( +2 \) and \( +4 \) oxidation states,
but these are less common and occur only in certain cases (e.g., Eu\(^{2+}\), Ce\(^{4+}\)).
The \( +5 \) oxidation state is very rare and not typical for lanthanoids.