Why is the oxidation number of oxygen?
The oxidation number of oxygen can vary.
According to oxidation state rules, any element that is not combined with other elements in a compound is zero.
Neutral compounds have net zero charge, so the charges of elements in a compound must equal zero.
Due to its high electronegativity, oxygen usually has a negative two charge. For example in the compound, calcium oxide, CaO, calcium has a oxidation number of +2 and the oxygen has -2 charge.
In peroxides, such as hydrogen peroxide,
That means that oxygen component,
Fluorine is the most electronegativity element and when it combines with oxygen to form oxygen difluoride,