a) BaO is barium oxide. Barium has oxidation number +2 and oxygen has oxydation number -2.
b) K₂S is potassium sulfide. Potassium oxidation number is +1 and sulfur -2.
c) CaCl₂ is calcium chloride. Calcium has +2 and chlorine -1 oxidation number.
d) Cs₂S is cesium sulfide. Cesium has +1 oxidation number.
e) Al₂O₃ is aluminium oxide. Aluminium has +3 oxidation number.
f) CaBr₂ is calcium bromide. Bromine has -1 oxydation number.
g) SrI₂ is strontium iodide. Strontium is +2 and iodine is -1.
h) Mg₃N₂ is magnesium nitride. Nitrogen has -3 oxidation number.