Answer:
NH₄CN, NH₄IO₃, Fe(CN)₃, Fe(IO₃)₃
Step-by-step explanation:
Cations (positively charged ions) can only form ionic bonds with anions (negatively charged ions). However, you can't just simply put one cation and one anion together to form a compound. Each compound needs to been neutral, or have an overall charge of 0. When cations and anions do not have charges that perfectly cancel, you need to modify the amount of each ion in the compound.
1.) NH₄CN
-----> NH₄⁺ and CN⁻
-----> +1 + (-1) = 0
2.) NH₄IO₃
-----> NH₄⁺ and IO₃⁻
-----> +1 + (-1) = 0
3.) Fe(CN)₃
-----> Fe³⁺ and CN⁻
-----> +3 + (-1) + (-1) + (-1) = 0
4.) Fe(IO₃)₃
-----> Fe³⁺ and IO₃⁻
-----> +3 + (-1) + (-1) + (-1) = 0