Question

The symbol of element with atomic radius of Ga as compared to Al is
a) Nh
b) Ni
c) No
d) Nb

Answer 1

Gallium has one more shell in it than aluminium. ... This is because Ga has 3 d electrons, which has poor shielding effect. So, the effective nuclear charge on the outermost electrons is higher than Al, as a result of which the atomic radii decreases and is lower than Al.

Therefore, Ni.