What is the common oxidation state of oxygen in most compounds?

In most compounds, oxygen commonly exhibits an oxidation state of -2. This is primarily due to its high electronegativity, which allows it to attract electrons effectively. When oxygen forms compounds, it typically gains two electrons to achieve a stable electron configuration similar to that of the noble gases. This results in the -2 oxidation state.

In addition, the -2 oxidation state is consistently observed in a variety of compounds, such as oxides (e.g., H2O, CO2) and in many ionic salts where oxygen is present as the oxide ion (O^2-). This characteristic facilitates the formation of stable bonds with other elements, particularly metals, typically forming ionic or covalent substances.

Understanding this common oxidation state is critical for predicting the behavior of oxygen in chemical reactions and in the formation of different compounds.