Chemical Bonding: N₃^- Lewis Structure

Drawing the Lewis Structure for N₃^-

Viewing Notes:

• There are a total of 16 valence electrons in the N₃^- Lewis structure.
• With N₃^- you'll need to form two double bonds between the Nitrogen atoms to fill the octets and still use only the 34 valence electrons available for the molecule.
• Put brackets and a negative sign around the N₃^- Lewis structure to show that it is an ion.

Transcript: This is the N3- Lewis structure: the Azide ion. Nitrogen is in group 5, also called 15, on the periodic table. It has 5 valence electrons. We have 3 Nitrogens. And then we have this negative sign up here so we're going to add an additional electron, for a total of 16 valence electrons. First, we'll put the three Nitrogens in a line and then we'll distribute electrons around the N3- Lewis structure.

We'll put two electrons between atoms to form the chemical bonds--we've used 4, and then 6, and then 16. So we've used all 16 valence electrons that we have to work with. The Nitrogens on the outside have full outer shells; they have octets. But the Nitrogen in the center only has 4 valence electrons. We can move a pair of electrons from the outside into the inside to form a double bond and share those electrons with the central atom. So we still have 8 valence electrons on this Nitrogen. But now we have six valence electrons on the central Nitrogen.

So we're getting closer to an octet. If we move these electrons in the center and form a double bond, we'll find that the central Nitrogen now has an octet and we're still only using 16 valence electrons. So that's the Lewis structure for N3-, the Azide ion. We've used all 16 valence electrons.

All of the atoms have octets, so we're done. This is Dr. B. with the N3- Lewis structure. Thanks for watching.