How would you draw all of the resonance structures for nitrate?

To draw all of the resonance structures for the nitrate ion ((NO_3^-)):

1. Start with a nitrogen atom (N) in the center and three oxygen atoms (O) surrounding it. Nitrogen is the central atom because it is less electronegative than oxygen.

2. Draw single bonds from the nitrogen atom to each oxygen atom. This will use up 3 of the 5 valence electrons of nitrogen and 3 of the 6 valence electrons for each oxygen (as each oxygen atom shares one electron with nitrogen).

3. To complete the octet for each oxygen, add lone pairs. Each oxygen atom will have two lone pairs, using up 6 of its valence electrons (including the one shared with nitrogen).

4. Now, you need to account for the negative charge on the nitrate ion. Since nitrogen has 5 valence electrons and it has used 3 in bonding, you have 2 electrons left to be placed. These can be represented as a lone pair on the nitrogen, but to account for the overall -1 charge of the ion, one of the oxygen atoms must carry an extra electron as a lone pair, resulting in a formal negative charge on that oxygen.

5. To create resonance structures, you can move the double bond (or the location of the extra electron) among the three oxygen atoms. In one structure, the double bond can be between nitrogen and one of the oxygen atoms, with the other two oxygens having single bonds to the nitrogen and holding a lone pair that accounts for the negative charge. Then, for the resonance structures, move the double bond to each of the other two oxygen atoms in turn, with the corresponding adjustment of the formal charge.

6. Make sure each resonance structure has a complete octet for all atoms and that the overall charge of the ion is -1.

In summary, the nitrate ion will have three resonance structures, each with a double bond between the nitrogen and one of the oxygen atoms, and the other two oxygens connected by single bonds. Each structure will show a different oxygen atom carrying the formal negative charge. These structures are equivalent in terms of energy and contribute equally to the hybrid resonance structure of the nitrate ion.