Answer:
The most common oxidation state of fluorine is -1.
Oxidation state
The oxidation state of an atom can be defined as the hypothetical charge that would be held by that atom if all of its bonds to other atoms were completely ionic in nature.
Fluorine and other halogens have an oxidation number –1 when they appear as halide ions in their compounds. When iodine, chlorine, and bromine are combined with oxygen, their oxidation number is positive.