1. Draw the Lewis Structure

* Nitrogen (N): 5 valence electrons

* Oxygen (O): 6 valence electrons each

* Total valence electrons: 5 + (2 x 6) + 1 (from the negative charge) = 18

The Lewis structure for nitrite has a double bond between one nitrogen and one oxygen, and a single bond between nitrogen and the other oxygen. The oxygen with the single bond has a negative charge.

2. Assign Formal Charges

* Formal Charge = (Valence Electrons) - (Non-bonding Electrons) - (1/2 Bonding Electrons)

* Nitrogen:

* Valence Electrons: 5

* Non-bonding Electrons: 0

* Bonding Electrons: 8 (4 bonds)

* Formal Charge = 5 - 0 - (1/2 * 8) = +1

* Oxygen (double bonded):

* Valence Electrons: 6

* Non-bonding Electrons: 4

* Bonding Electrons: 4

* Formal Charge = 6 - 4 - (1/2 * 4) = 0

* Oxygen (single bonded):

* Valence Electrons: 6

* Non-bonding Electrons: 6

* Bonding Electrons: 2

* Formal Charge = 6 - 6 - (1/2 * 2) = -1

Conclusion

The formal charges of nitrite are:

* Nitrogen: +1

* Double-bonded Oxygen: 0

* Single-bonded Oxygen: -1