You're asking about FeBr2, which is the chemical formula for iron(II) bromide. To figure out how many iron atoms are in a molecule of FeBr2, look at the subscripts in the formula:

* Fe has a subscript of 1 (even though it's not written).

* Br has a subscript of 2.

This means there is one iron atom (Fe) and two bromine atoms (Br) in each molecule of FeBr2.