What is the correct formula unit for the ionic compound, ferric oxide?

Question

? FeO
? Fe2O
? Fe3O4
? Fe3O2
? Fe2O3

Answer 1

The correct formula unit for ferric oxide is ${\text{Fe}}_2{\text{O}}_3$. Ferric indicates that iron is present in the +3 oxidation state, and since oxygen typically has a -2 charge, the formula reflects the balance of charges. Therefore, the correct answer is ${\text{Fe}}_2{\text{O}}_3$.