Hydrazine, with a chemical formula of N2H4, has 14 valence electrons. If we draw the Lewis structure of hydrazine, the two N atoms are adjacent while the 4 H atoms surround the N atom at the top and at the side. Since each H is attached to 2 valence electrons, and N is attached to N, a total of 10 valence electrons is already paired. This leaves 2 lone-pairs of valence electrons for each N atom.
