The hydrogen-nitrogen bond is the third least polar of all of these bonds. Polarity in a bond is caused by an electronegativity difference of the atoms. Electronegativity is the attraction of an atom for its outer electrons and is based on both the number of protons in the nucleus and the distance of the electrons from the nucleus.

The order of electronegativity for the most useful elements is...

F > O > Cl > N > Br > I > S > C and H > metals