Question

Aluminium exhibits +3 oxidation state. As we move down the group, +1 oxidation states get more stable. This is a consequence of :

• A. increasing size of the atom
• B. inert pair effect
• C. electron deficient nature
• D. $p\pi$-$p\pi$ bonding

Answer 1

The correct option is B inert pair effect

Answer:- (B) inert pair effect

The atoms of group 13 elements have 3 valence electrons, two in s-subshell and one in p subshell.

The +1 oxidation state becomes more stable as we move down to the group due to inert pair effect. After the removal of 1 electron from p orbital, the remaining $n{s}^2$ electrons behave like stable noble gases due to inert pair effect and do not take part in compound formation. The two electrons present in the s-shell are strongly attracted by the nucleus and do not participate in bonding. This inert pair effect becomes more and more prominent on moving down the group.

Hence, the +1 oxidation state gets more stable as we move down the group.