What oxidation number does oxygen typically have?

Oxygen typically has an oxidation number of -2 in most of its compounds. This is due to its high electronegativity, which means it tends to attract electrons towards itself when forming bonds with other elements. In the vast majority of chemical reactions and compounds, such as water (H2O) and carbon dioxide (CO2), oxygen is found with a -2 oxidation state.

This -2 oxidation number reflects that each oxygen atom gains two electrons, corresponding to the two additional electrons it requires to complete its valence shell. In peroxides, where oxygen is bonded to another oxygen, the oxidation state can be -1, but this is a less common scenario. Additionally, in compounds with fluorine (like OF2), oxygen can have a +2 oxidation state, but these are exceptions rather than the rule.

Overall, the conventional -2 oxidation state is the standard for understanding oxygen's behavior in chemical reactions and compounds, making it the most likely choice in this context.