Which of the following is the correct chemical formula for the iron(II) ion?

• A. Fe^{3+}
• B. Fe^{+}
• C. Fe_2^{+}
• D. Fe^{2+}

Answer: (D)

Verified step by step guidance

1. Understand that the Roman numeral in parentheses indicates the oxidation state (charge) of the ion. Here, iron(II) means iron has a +2 charge.
2. Recall that the chemical symbol for iron is Fe.
3. Combine the symbol Fe with the charge indicated by the Roman numeral II, which corresponds to a 2+ charge.
4. Write the ion with the charge as a superscript: \(Fe^{2+}\).
5. Verify that the charge matches the oxidation state given (II means +2), confirming that \(Fe^{2+}\) is the correct formula for the iron(II) ion.