Drawing the Lewis Structure for NO2- (Nitrite Ion)

Viewing Notes:

  • The Lewis structure for NO2- (Nitrite Ion) comes up quite often in chemistry.
  • Be sure to put brackets, along with a negative sign, around the NO2- Lewis structure when you are done to show that it is an ion with a negative charge.
  • NO2- has a total of 18 valence electrons.

Transcript: This is the NO2- Lewis structure: the nitrite ion. For Nitrogen we have 5 valence electrons; 6 for Oxygen, but we have two Oxygens so we'll multiply that by two; plus one for this valence electron up here; gives us a total of 18 valence electrons for the NO2- Lewis structure. Nitrogen is the least electronegative, we'll put that in the center and we'll put the Oxygens on either side. We have a total of 18 valence electrons. We'll put two between atoms to form chemical bonds. We've used 4, then around the Oxygen atoms, 6, 16, and then back to the central Nitrogen, 18.

So we've used all 18 valence electrons. The Oxygens each have eight valence electrons, but the central Nitrogen only has six. So we're going to have to fix that. Let's take two valence electrons here from the Oxygen and share them to form a double bond. Now the Nitrogen has an octet, eight valence electrons, and the Oxygen still has eight, as well. So we've used all 18 valence electrons and satisfied the octets on each of the atoms.

If we were to check the formal charges, you'd see that one of the Oxygens, the one on the left, has a negative one formal charge. That makes sense, because the nitrite ion has a negative charge, as well. One last thing: since it is a negative ion, we need to put brackets around it to show that it is an ion.

So that's the Lewis structure for NO2-. This is Dr. B., and thanks for watching.