Question

Arrange the following elements in increasing order of their size.

$B,Al,Ga,In,Ti$

• A. $B$ < $Al$ $\approx$ $Ga$ < $In$ $\approx Ti$
• B. $Al$ < $B$ $\approx$ $Ga$ < $In$ $\approx Ti$
• C. $B$ < $Al$ $\approx$ $Tl$ < $In$ $\approx Ga$
• D. None of these

Answer 1

The correct option is A $B$ < $Al$ $\approx$ $Ga$ < $In$ $\approx Ti$

Down the group, size increases but in some cases like in group $IV$, even though the shell increases. But due to poor shielding effect, the effect of the addition of a new shell and increased charge at centre cancel each other.

Hence, the correct order will be $B<Al\approx Ga<In\approx Ti$.