Confused on how to do this

Question

Write the empirical formula for at least four ionic compounds that could be formed from the following ions: NO−3, Fe3+, Fe2+, ClO−3

Answer 1

You need to learn to write the ions correctly.

NO-3 should be NO₃^- or NO3^- (since NO-3 doesn't exist)

Same for ClO-3. It should be ClO₃^- or ClO3^-

Given these considerations, you can write the following ionic compounds, as explained by @Tiffany K.

Fe³⁺ + ClO₃^- = Fe(ClO₃)₃

Fe²⁺ + NO₃^- = Fe(NO₃)₂

Fe²⁺ + ClO₃^- = Fe(ClO₃)₂

Fe³⁺ + NO₃^- = Fe(NO₃)₃

Answer 2

Fe⁺³ + NO^-3 = Fe(NO) - you can combine ions with different charge signs (+ and -). take the numeric charge and place it at the bottom of the opposite ion. So for Fe⁺³ + NO^-3 = Fe₃(NO)₃ Because the number of the charge is the same, you can simply for the formula to Fe(NO).

Fe⁺³ + ClO^-3 = Fe(ClO)

Fe⁺² + NO^-3 = Fe₃(NO)₂,

Fe⁺² + ClO^-3 Fe₃(ClO)₂