The Lewis structure for nitrogen monoxide is an N surrounded by three dots and connected by two pairs of dots to an O that is surrounded by four additional dots. The two atoms of nitrogen monoxide are represented by an N for nitrogen and an O for oxygen.
In the Lewis structure for nitrogen monoxide, each valence electron is represented by a dot. The pairs of dots that connect the two elemental symbols together are the bonds that connect the atoms in the compound. The number of dots must equal the number of valence electrons in the represented compound, which is 11 valence electrons for nitrogen monoxide. Since the compound has an odd number of valence electrons, it has one unpaired electron that must be placed in a way to give the structure the lowest possible formal charge.
The formal charge is found by subtracting the number of unpaired electrons on an atom plus the number of bonds on the atom from the number of valence electrons the atom would have on its own. The formal charge of the nitrogen is plus five, while the formal charge of the oxygen is zero. By adding the lone electron to the nitrogen, a molecule of nitrogen monoxide carries an overall charge of zero.