Final answer:
When writing formulas for ionic compounds, the crisscross method is used to determine the correct ratio of ions involved. The chemical names for FeO and Fe2O3 are iron(II) oxide and iron(III) oxide, respectively.
Step-by-step explanation:
When writing the formulas for ionic compounds, we need to use the crisscross method to determine the correct ratio of the ions involved. In an ionic compound, the charges of the positive and negative ions must balance out to zero. The crisscross method allows us to determine the correct subscripts for each ion by taking the absolute values of each ion's charge and swapping them.
For example, in FeO, iron (Fe) has a charge of +2 and oxygen (O) has a charge of -2. When using the crisscross method, we swap the charges and write the subscripts as Fe2O2, which simplifies to FeO. Similarly, in Fe2O3, iron (Fe) has a charge of +3 and oxygen (O) has a charge of -2. The crisscross method gives us Fe2O3, which represents the correct ratio of ions.
The chemical names for FeO and Fe2O3 are iron(II) oxide and iron(III) oxide, respectively.
Learn more about Writing formulas for ionic compounds