Which of the following is the correct chemical formula for zinc iodide?

• A. ZnI
• B. Zn2I
• C. ZnI2
• D. Zn2I2

Answer: (C)

Verified step by step guidance

1. Step 1: Identify the charges of the ions involved. Zinc (Zn) typically forms a +2 charge as Zn^{2+}, and iodide (I) forms a -1 charge as I^{-}.
2. Step 2: Determine the ratio of ions needed to balance the overall charge to zero. Since Zn^{2+} has a +2 charge and I^{-} has a -1 charge, two iodide ions are needed to balance one zinc ion.
3. Step 3: Write the chemical formula by combining one Zn^{2+} ion with two I^{-} ions, resulting in ZnI_{2}.
4. Step 4: Verify that the total positive charge (+2 from Zn) and total negative charge (2 × -1 from iodide) sum to zero, confirming the formula is electrically neutral.
5. Step 5: Conclude that the correct chemical formula for zinc iodide is ZnI_{2}.