Question

Which of the following is the correct order for the increasing atomic radius?

• A. $Al<Ga<Be<Li$
• B. $Be<Ga<Al<Li$
• C. $Al<Ga<Li<Be$
• D. $Al<Be<Ga<Li$

Answer 1

The correct option is B $Be<Ga<Al<Li$

Atomic radius increases down a group and decreases as we move from left to right across a period. So, from $Li$ to $Be$ atomic radius decreases.
But due to poor shielding of $d$-electrons, atomic radius of $Ga$ is smaller than that of $Al$.