Question

(iv) Which pair of element belong to same group?
(a) (A,B)
(b) (B,C)
(c) (C,D)
(d) (D.E)​

Answer 1

The elements with the same valence electrons belong to the same group. The pair of atomic numbers 13 and 31, represents elements belonging to the same group. They correspond to Al and Ga.

Answer 2

The pair of atomic numbers 13 and 31, represents elements belonging to the same group. They correspond to Al and Ga. They belong to group 13 or IIIA.