# How would you calculate the formal charge of NH3?

Nov 5, 2015

One Nitrogen atom = $1$ x $- 3$ (nitrogen's charge) = $- 3$

Three hydrogen atoms = $3$ x $+ 1$ (hydrogen's charge) = $3$

$- 3 + 3 = 0$ (net charge of $N {H}_{3}$)

#### Explanation:

If you refer to a periodic table you'll see columns. The elements in hydrogen's column have a $+ 1$ charge. The elements in nitrogen's column have a $- 3$ charge.

You can determine the charge of the nitrogen column by starting with the noble gases(charge = $0$) and counting down by column. Similarly the hydrogen column starts with $+ 1$ while the next column to the right is $+ 2$.

Transition metals are typically $+ 3$, although there are a few exceptions.