What is the charge on the nitrate ion?

The nitrate ion has a molecular formula of NO3. In this structure, nitrogen (N) is the central atom bonded to three oxygen (O) atoms. Each oxygen has a typical oxidation state of -2. Therefore, the total contribution from the three oxygen atoms is -6.

To maintain charge balance, the nitrogen must have a positive oxidation state of +5. When you sum the oxidation states of nitrogen (+5) and the three oxygens (-6), the overall charge becomes:

+5 - 6 = -1.

This indicates that the nitrate ion has a formal charge of -1, making it a negatively charged ion. Thus, the charge on the nitrate ion is indeed -1.