This from ionic compounds escape room

Fe2O3 - S

PbO2 - D

PbO - I

Fe2O - U

Fe(OH)3 - H

FeO2 - T

FeO - R

Pb2O - G

Pb(OH)2 - O

FeOH - N

Pb(OH)3 - A

Explanation:

In writing the formula of ionic compounds we consider the valency or oxidation state of each ion.

For instance, given the compound iron II oxide. The oxidation states of both iron and oxygen are +2 and -2 respectively. Ignoring the charges, this cancels out and we have FeO as the correct formula of the compound.

For Iron III oxide, the oxidation states of iron and oxygen are +3 and -2 respectively, the both atoms exchange charges. If we ignore the signs and write the exchanged numbers as subscripts we obtain the formula Fe2O3.