Answer
Iron(II)oxide: $FeO$
Iron(III)oxide: $Fe_{2} O_{3}$
Work Step by Step
The presence of -ide in oxide means it is a monoatomic anion.
Iron(II) means the charge of iron is +2, Oxide anion has a -2 charge. Thus the charges are balanced. Therefore, the chemical formula of Iron(II)oxide is $FeO$.
Iron(III) means the charge on iron is +3, and the charge on oxide anion is -2. In order to balance these charges, 2 atoms of Iron(II) should be present ( $ +3 \times 2 = +6 $) and 3 atoms of oxide anion should be present ( $-2 \times 3 =-6$). Therefore, the chemical formula should be $Fe_{2} O_{3}$.
