Q. In III A group (thalium) show + 1 oxidation state while other members show + 3 oxidation state, why?
A) Presence of lone pair of electron in $Tl$
B) Large ionic radius of $Tl$ ion
C) Inert pair effect
D) None of the above
Explanation
The correct answer is Option C: Inert pair effect.
A detailed explanation for this question is being prepared.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.