Lewis Structure for NO3-

[Kathryn 1F]

How would we draw the most stable Lewis structure for NO3-?
The midterm asked why the bond lengths were the same for this structure, which suggests that they were all single or double bonds, but I can't make it work with the octets?

[705170809]

NO3- has resonance, which allows all the bond angles to be the same between the different resonance structures since resonance doesn't move the actual formation of the atoms, but only rearranges the double bonds. Since NO3- has resonance, there are three different "most stable" structures, but all of them are similar in that the N is bonded to two Os with 6 surrounding lone pairs, and double bonded to one O with 4 surrounding lone pairs.

[Clarissa Cabil 1I]

For the lewis structure of NO3-, N is the central atom and there are 3 oxygens surrounding it. One of the oxygens has a double bond with N, and the other two oxygens have a single bond with N because nitrogen is in period 2, so it cannot have more than 4 bonds.

All the bond lengths are the same because the molecule has 3 resonance structures and the bond lengths are an average of the three resonance structures.

[Dayna Pham 1I]

I agree with 705 and Clarissa that the reason that the bond lengths are the same is because of the resonance structures. This is due to the delocalization of electrons, creating a single-double bond hybrid, so all the bond lengths are actually the same.