It is basically the measurement of the strength of the chemical bond .
It is the standard enthalpy shift that will occur or take place when the bond gets homo lytically cleaved into the fragments or the radical species be it like and .
So, in the Nitrogen molecule () there is the presence of triple bond () .
Hence for the breaking of this bond for getting involved in the reactions, a very large amount of bond dissociation energy must be required.
So, Nitrogen element would be inactive.
Therefore, Nitrogen is relatively inactive element becausebond dissociation energy of its molecule is fairly high.