Iron(II) iodate Express your answer as a chemical formula.
The correct answer and explanation is:
Correct Answer: Fe(IO₃)₂
Explanation:
Iron(II) iodate is an ionic compound made up of iron in the +2 oxidation state (Iron(II)) and the iodate ion (IO₃⁻). To determine the correct chemical formula, it is important to understand the charges on each of the ions involved and how to balance them.
Iron is a transition metal and can have more than one possible charge. In this case, the Roman numeral II in Iron(II) indicates that the iron ion has a +2 charge. Therefore, the iron cation is Fe²⁺.
The iodate ion is a polyatomic ion with the formula IO₃⁻. Each iodate ion has a charge of -1. To balance the charges in an ionic compound, the total positive charge must equal the total negative charge.
Since Fe²⁺ has a +2 charge and each IO₃⁻ has a -1 charge, two iodate ions are needed to balance one iron(II) ion:
Fe²⁺ + 2 IO₃⁻ → Fe(IO₃)₂
This gives a neutral compound where the total positive and negative charges are equal:
- Total positive charge: +2 from one Fe²⁺
- Total negative charge: 2 × (-1) = -2 from two IO₃⁻ ions
The formula of iron(II) iodate is therefore written as Fe(IO₃)₂. The parentheses around IO₃ indicate that more than one of the entire polyatomic ion is present in the formula. Parentheses are always used in chemical formulas when a polyatomic ion appears more than once in the compound.
Iron(II) iodate is often found in chemical reactions involving oxidation or precipitation processes. It is not very soluble in water, like many iodates, and can decompose upon heating, releasing iodine-containing gases. Understanding how to write the formula correctly is key for predicting behavior in chemical equations and reactions.