Is oxygen a metal or nonmetal?

1. Metal: The elements are said to be metal if they can lose their electron to form a cation.
2. Example of metal: $\mathrm{Li},\mathrm{Na},\mathrm{Mg},\mathrm{Ca}$ etc.
3. Nonmetal: The elements have a tendency to accept the electron and form anions called nonmetal.
4. Example of nonmetal: $\mathrm{Cl},\mathrm{Br},\mathrm{I}$ etc.
5. As oxygen has a tendency to accept the electron and form anion. So oxygen behaves as nonmetal.
6. Oxygen is the most abundant nonmetal on the earth.

Hence, oxygen is nonmetal.