* Bromine (Br) typically has an oxidation number of -1 in its compounds (except in compounds with oxygen).
* The overall charge of a neutral compound is 0.
Since there is only one Fe and one Br atom in FeBr, to balance the -1 charge of Br, the Fe must have a +1 oxidation number.
Therefore, the oxidation number of Fe in FeBr is +1.
