Question

What is the oxidation number of $\mathrm{N}$ in ${\mathrm{NO}}_3^{-}$?

Answer 1

1. The oxidation state or oxidation number can be defined as the loss or gain of electrons from an atom, molecule, or ion to achieve a stable electronic configuration.
2. Each element shows a different oxidation state depending upon the total number of valence shell electrons.
3. Nitrogen is a chemical element with atomic number 7.
4. The nitrate ion is having -1 charge on it and thus it is not a neutral atom.

Given oxidation state

• Oxygen gains 2 electrons to attain noble gas configuration and therefore it shows a -2 oxidation state.
• Let the oxidation state of nitrogen be x.

Calculating the oxidation number

• The oxidation number can be calculated as follows:
• $\left(\mathrm{No}.\mathrm{of}\mathrm{Nitrogen}\mathrm{atom}\right)\left(\mathrm{Oxidation}\mathrm{number}\mathrm{of}\mathrm{Nitrogen}\right)+\left(\mathrm{No}.\mathrm{of}\mathrm{Oxygen}\mathrm{atom}\right)\left(\mathrm{Oxidation}\mathrm{number}\mathrm{of}\mathrm{Oxygen}\right)=-1$
• $\left(1\right)\left(\mathrm{x}\right)+\left(3\right)\left(-2\right)=-1$
• $\mathrm{x}=+5$
• Therefore, the oxidation state of $\mathrm{N}$ in ${\mathrm{NO}}_3^{-}\mathrm{is}+5.$