What is the significance of the oxidation number of oxygen in most compounds?

Oxygen typically has an oxidation number of -2 in most of its compounds, which makes this answer significant in understanding chemical behavior. This consistent oxidation state is crucial because it helps predict how oxygen will interact with other elements and compounds.

For example, in water (H₂O), oxygen's -2 oxidation state helps balance the +1 oxidation state of the hydrogen atoms, resulting in a neutral compound overall. In addition, this stable oxidation number plays a vital role in redox reactions, where oxygen often serves as an oxidizing agent, facilitating the transfer of electrons from other elements.

While there are exceptions, such as in peroxides where oxygen has an oxidation number of -1 or in superoxides where it is -1/2, the predominance of the -2 state underscores its reliability in most chemical contexts. This consistent behavior is fundamental in both organic and inorganic chemistry, enabling the understanding of reactions and the properties of various substances containing oxygen.