Which Group 15 element exists as diatomic molecules at STP?
(1) phosphorus (3) bismuth
(2) nitrogen (4) arsenic



Answer :

Nitrogen exists as diatomic molecules at STP. 

Answer: The correct option is 2.

Explanation: Group 15 elements are Nitrogen, phosphorous, Arsenic, Antimony, Bismuth.

To know whether an element exits as a diatomic molecule or not, we look at the atomicity of an element.

Atomicity is the number of atoms of an element combining to form a molecule.

Atomicity of Nitrogen = 2

Atomicity of Phosphorous = 4

Atomicity of Bismuth = 1

Atomicity of Arsenic = 1

The element having atomicity 2 will exist as a diatomic molecule.

Hence, Nitrogen is a diatomic molecule [tex](N_2)[/tex]