Answer:
CaBr₂, CaO, FeBr₂, FeO
Explanation:
Per binary compound, there must be 1 cation (Ca²⁺, Fe²⁺) and 1 anion (Br⁻, O²⁻). The compound should have a charge of 0 (neutral). For this to occur, there sometimes needs to be more than one cation/anion present in the compound. Below I have included the math that displays why there are more ions necessary in some compounds.
CaBr₂
-----> Ca = +2 and Br = -1
-----> +2 + (-1) + (-1) = 0
CaO
-----> Ca = +2 and O = -2
-----> +2 + (-2) = 0
FeBr₂
-----> Fe = +2 and Br = -1
-----> +2 + (-1) + (-1) = 0
FeO
-----> Fe = +2 and O = -2
-----> +2 + (-2) = 0
