Question

Which among the following can show the maximum of four covalencies?

• A. $Al$
• B. $Ga$
• C. $In$
• D. $B$

Answer 1

The correct option is D $B$

Option $\left(D\right)$ is correct.

Boron shows the maximum of four covalencies as it has only four orbitals in its outermost shell (e.g. $B{H}_4^{-}$).Other elements of the group show covalency of even six due to the presence of $d-$ orbitals in them(e.g. $\left[Al\right(OH{)}_6{]}^{3-}$).