# How do we utilize Lewis structure in simple species such as nitrate ion?

Apr 4, 2017

Lewis structure is simply electron counting..........

#### Explanation:

Let's take the nitrate, anion, $N {O}_{3}^{-}$. Nitrogen comes from Group 15, and has five valence electrons, oxygen comes from Group 16, and has six valence electrons.

And thus we have to distribute $5 + 3 \times 6 + 1 = 24$ $\text{electrons}$ around the nitrate core...........Why did I add an extra electron?

And thus, $O = {N}^{+} {\left(- {O}^{-}\right)}_{2}$, distributes $6$, $4$, and $2 \times 7$ valence electrons around $O =$, $N$, and ${O}^{-}$ respectively, and this (with the 2 inner core electrons) accounts for the charge on the atom, neutral, positive, or negative: i.e. N, Z=7;O, Z=8.

As always, the charge on the atom is the difference between the nuclear charge, and the electronic charge. For more of the same see here.

What about $N {H}_{3}$, and $N {H}_{4}^{+}$?