It is not correct to say that the electronegativity of nitrogen in all compound is 3. It depends upon its state of hybridization in a particular compound. It may be noted that greater the percentage of s-character, more will be the electronegativity of the element. Thus, the electronegativity of nitrogen increases in moving from sp3 hybridised orbitals to sp hybridised orbitals i.e. as sp3 <sp2 <sp.
