question_answer 1)

How would you explain the lower atomic radius of \[Ga\]as compared to Al?

Answer:

Due to poor shielding of the valence electrons in \[Ga\] by the inner d-electrons, the effective nuclear charge is high in comparison to Al. As a result, the attractive force with which the valence electrons are attracted is high. This brings contraction in size and hence, atomic size of \[Ga\] is lower in comparison to Al.