To determine the formula of the compound formed between Fe3+ ions and NO3– ions, we need to consider the charges of the ions.
Iron (Fe) in this case has a charge of +3, which is represented as Fe3+. The nitrate ion (NO3–) carries a charge of -1. To balance the charges in the compound, we need to combine these ions in such a way that the total positive charge equals the total negative charge.
Since Fe3+ has a +3 charge, we will need three nitrate ions to balance it out because three NO3– ions will provide a total charge of -3. Therefore, the formula for the resultant compound will be:
Fe(NO3)3
This indicates that one iron ion is combined with three nitrate ions, forming iron(III) nitrate.