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.
