Question

Which of the following elements of group V-A does not show allotropy?
(a)- N
(b)- Bi
(c)- P
(d)- As

Answer 1

Group V-A is the name of the group given by Mendeleev in its Mendeleev's periodic table, as Group V-A is group 15. If the element is found only in one solid form then it is said that the element does not have an allotropic form.

Complete answer:
The term allotrope refers to one or more physical forms in the same physical condition of a chemical element. Allotropes may have chemical and physical characteristics differing. The notion of allotropy was developed by the Swedish scientist Jons Jakob Berzelius in 1841. The word "allotropy," which indicates changeability, originates from the Greek term allotropy.
Group V-A is the name of the group given by Mendeleev in Mendeleev's periodic table, as Group V-A is group 15. The elements of this group are nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi).
There are two allotropes of nitrogen element. As we know that nitrogen is present in gaseous form but the solid form of nitrogen has alpha-nitrogen form and beta-nitrogen form.
There are three allotropic forms of phosphorus, i.e., white phosphorus, red phosphorus, and black phosphorus.
There are two allotropic forms of arsenic, i.e., yellow form and grey form.
There are two allotropic forms of antimony, i.e., yellow form and grey form.
Bismuth is found only in one form bismuth and it does not show allotropy.

Therefore, the correct answer is an option (b)- Bi

Note:
Some of the allotropic forms are not stable but some of them are stable allotropic forms. As we move down a group, the inert pair effect increases down and the bismuth due to the inert pair effect does not show variable oxidation states.