Answer: The charge of nitrate ion (NO3) is -1.
Charge of NO3
The chemical formula NO3 represents the nitrate ion. Nitrate is a polyatomic ion composed of one nitrogen (N) atom and three oxygen (O) atoms. The overall charge of the nitrate ion is negative, and it carries a charge of -1.
Understanding the Charge of NO3
To understand the charge of the NO3 ion, we can break down its components:
- Nitrogen (N): Nitrogen in nitrate has an oxidation state of +5. This indicates that it has lost 5 electrons in its bonding with oxygen.
- Oxygen (O): Each oxygen atom typically has an oxidation state of -2. Since there are three oxygen atoms, the total contribution of the oxygen atoms is 3 × (-2) = -6.
In the nitrate ion, the sum of the oxidation states must balance the overall charge of the ion. Therefore, the nitrogen’s +5 charge and the oxygen’s total -6 charge result in a net charge of -1:
\[ +5 + 3(-2) = +5 – 6 = -1 \]
Why NO3 Has a Negative Charge
The negative charge of NO3– arises because there are more electrons than protons within the ion. Nitrate has an extra electron that is not neutralized by a proton, giving it a -1 charge. This makes NO3 an anion, which means it is negatively charged and often pairs with positive ions (cations) to form compounds like sodium nitrate (NaNO3).
Applications of NO3
Nitrate ions are common in various chemical processes and are widely found in fertilizers, explosives, and food preservatives. Their ability to form compounds with cations like sodium (Na+) or potassium (K+) makes them useful in agriculture and industry.
Conclusion
The charge of the nitrate ion (NO3) is -1. This is due to the balance between the nitrogen atom’s oxidation state of +5 and the combined oxidation state of the three oxygen atoms (-6), resulting in a net charge of -1.