Question

How to Write the Formula for Iron (III) oxide?

Answer 1

Answer: Fe₂O₃

Step-by-step explanation:

iron (III) oxide

Fe is the symbol for iron. O is the symbol for oxygen.

You know the charge on iron is +3 due to the (III) written after iron.

You know the charge on oxygen is -2.

Use the "swap and drop" method to write the formula. Swap the numbers and then drop them as subscripts. Fe subscript becomes 2. O subscript becomes 3.

Fe³⁺ O²⁻

Fe₂O₃

Answer 2

Fe2O3
The numbers are subscript. The iron here has a charge of +3 and O has a charge of -2. For it to be equal you need 2 Fe and 3 O
Hence Fe2O3