How do we draw the Lewis structure of ammonia?

1 Answer
Oct 26, 2015

How many electrons from the individual elements: 3 from the hydrogen, and 5 valence electrons from the nitrogen.

Explanation:

So ammonia, NH_3, has 8 valence electrons to distribute. 6 electrons are utilized for the 3 N-H bonds, and the remaining 2 are localized on the nitrogen as a lone pair.

So we get :NH_3. Note that this is not the end of the story. Why have I represented each atom in the molecule as neutral? If I had ammonium ion, (NH_4)^+, the positive charge is associated with the nitrogen centre. For the nitrogen in ammonia, there are 7 positive nuclear charges (i.e. 7 nuclear protons). This charge is balanced by 2 inner core electrons, 2 electrons from the lone pair, and 3 electrons from the N-H bonds (i.e. the other electron in the N-H bond is formally assigned to the hydrogen).