Oxygen (O2) is a diatomic molecule composed of two oxygen atoms joined together by a covalent bond. Electronegativity measures the ability of an atom to attract electrons. In the case of O2, the electronegativity of each oxygen atom is 3.44 on the Pauling scale.

The electronegativity of oxygen is higher than that of most other elements, including hydrogen, carbon, and nitrogen. This means that oxygen atoms have a strong tendency to attract electrons from other atoms, forming polar covalent bonds. The electronegativity difference between oxygen and hydrogen atoms in water (H2O) is what gives water its polar character, with the oxygen atoms having a slight negative charge and the hydrogen atoms having a slight positive charge.