Question

Which is correct increasing order of their tendency of the given elements to form $M^{3 -}$ ion?

• A. Bi > Sb > As > P > N
• B. Bi < Sb < As < P < N
• C. N < P < Sb < Bi < As
• D. Bi > Sb $\sim$N $\sim$P > As

Answer 1

Answer: (B)

Bi < Sb < As < P < N

Answer 2

: On moving down the group, the stability of – 3 oxidation state decreases. This is due to the following reasons (i) On descending a group the size of the atom or ion increases. As a result, attraction of the nucleus per newly added electron decreases (ii) A large anion cannot fit easily into lattice of a small cation. (iii) As the negative charge on the ion increases, it becomes more and more susceptible to polarization.