The N-N bond, which is the bond between two nitrogen atoms, is classified as a nonpolar covalent bond. This classification arises from the nature of the bond and the elements involved.
To understand why it’s nonpolar, we first need to look at the electronegativity of nitrogen. Electronegativity is a measure of how strongly an atom can attract electrons in a bond. For nitrogen, its electronegativity is relatively high, around 3.0 on the Pauling scale. However, when two nitrogen atoms bond together, they have the same electronegativity and are, therefore, equal in their ability to attract shared electrons.
In a nonpolar covalent bond, the shared electrons are distributed evenly between the two atoms. Because both nitrogen atoms pull equally on the shared electrons, there is no charge separation, and thus, the bond remains nonpolar. If one of the nitrogen atoms had a significantly higher electronegativity than the other, we would then classify the bond as polar covalent, but that is not the case here.
Therefore, the N-N bond is a classic example of a nonpolar covalent bond, characterized by an even sharing of electrons and the absence of any charge difference between the two bonded atoms.