Question

The oxidation number of oxygen atom in $O^{2-}_2$ ion is

• A. -3
• B. -1
• C. -5
• D. -2

Answer 1

Answer: (D)

-2

Answer 2

Oxygen atom is monoatomic and oxidation number of an element in a monoatomic ion, is equal to the charge on the ion. i.e. -2.