Question

is the actual charge of an atom if it exists as a monoatomic ion.

• A. Atomic number
• B. Mass number
• C. Oxidation number

Answer 1

The correct option is C Oxidation number

Oxidation number (or oxidation state) is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom. In other words, it is the actual charge of an atom if it exist as a monoatomic ion when the atom loses or gains electrons.

For example, in hematite $\left({\text{Fe}}_2{\text{O}}_3\right)$, iron has an oxidation number of +3 as it loses three electrons to form ${\text{Fe}}^{+3}$ ion and form chemical bond with oxygen. Similarly, oxygen has an oxidation number of -2 as it gains two electrons to form ${\text{O}}^{-2}$ ion and form chemical bond with iron.