Question

Nitrogen does not form pentahalides. Give reason.

Answer 1

Hint:
Nitrogen contains five valence electrons in its valence shell and group which is having Nitrogen called as pnictogens and it belongs to p-block elements.

Complete answer:
Nitrogen is gaseous non metal,
The atomic number of Nitrogen is 7
Electronic configuration of Nitrogen is $1{s^2}2{s^2}2{p^3}$
Nitrogen belongs to 15 group
Nitrogen belongs to 2 period
Nitrogen is having two shells K –shell, and L-shell
L-shell is the valence shell of Nitrogen
The number of Valence electrons in Nitrogen is 5
The valency of Nitrogen is 3
Nitrogen forms trivalent electronegative ion that is ${N^{ - 3}}$
Nitrogen having 2 orbitals in its valence shell
The first orbital is s which is having 2 electrons which are paired
Second orbital is p orbitals ${p_x},{p_y},{p_z}$. Each orbital having one electron which unpaired
Total of five electrons in its valence shell. If it gains three more electrons than Nitrogen will get octet configuration which will become.
Octet configuration is defined as the atom that should contain 8 electrons in the valence shell.
So Nitrogen gains only three electrons in the p orbitals and forms a trivalent ion. The nitrogen valence shell is L –shell. L shell doesn’t hold d-orbitals, so Nitrogen doesn’t have vacant d-orbitals, so it cannot form expanded octet configuration.
So, Nitrogen is unable to give pentahalides, Nitrogen only forms trihalides.
Examples for Trihalides are $NC{l_{3\;}}\;,N{F_3}$

Note: d- orbitals present in M-shell but Nitrogen ends with L-shell. Nitrogen having only 3 unpaired electrons and after getting octet configuration, nitrogen can form a dative bond, but cannot form pentahalides.