Question

Explain why nitrogen is much less reactive than phosphorus?

Answer 1

We have to know that the strong triple-bond between the atoms in molecular nitrogen makes this compound difficult to break apart, and thus nearly inert. Liquid nitrogen is a useful coolant because it is inexpensive and has a low boiling point. Nitrogen is very unreactive because of the very strong triple bond between the nitrogen atoms.

Complete answer:
Nitrogen is chemically less reactive. This is because of the high stability of its molecule,${N_2}$. In ${N_2}$, the two nitrogen atoms form a triple bond. This triple bond has very high bond strength, which is very difficult to break. It is because of nitrogen's small size that it is able to form $p\pi - p\pi$ bonds with itself. This property is not exhibited by atoms such as phosphorus. Thus, phosphorus is more reactive than nitrogen. Nitrogen molecule is ${N_2}$ where two nitrogen atoms are triply bonded, in other words presence of triple bond makes the nitrogen bend strong and less reactive whereas phosphorus is a ${P_4}$ molecule where each phosphorus molecule is singly bonded, weak and hence more reactive. Nitrogen does not react readily as its bonds are strong making it stable. Pentavalente in phosphorus is more stable when compared to that of nitrogen even though they belong to the same group due to large size of phosphorus atom and greater ability to accommodate electrons.

Note:
As a result the energy of the bond dissociation is very high at room temperature ($946KJ/mol$). This reason leads to the fact that ${N_2}$ is very less reactive at room temperature. The strength of ${N_2}$triple bond makes the molecule very unreactive because it requires a large amount of energy to break the bond.