Which of the following is the correct chemical formula for calcium nitrate?

• A. Ca(NO_3)_2
• B. CaNO_3
• C. Ca_2(NO_3)_3
• D. Ca_3N_2

Answer: (A)

Verified step by step guidance

1. Identify the ions involved: calcium forms a Ca^{2+} ion, and the nitrate ion is NO_3^{-}.
2. Determine the charges on each ion: Ca^{2+} has a +2 charge, and NO_3^{-} has a -1 charge.
3. Balance the total positive and negative charges so the compound is electrically neutral. Since calcium has a +2 charge, you need two nitrate ions, each with a -1 charge, to balance it.
4. Write the formula by placing the calcium ion first, followed by the nitrate ion with a subscript of 2 to indicate two nitrate ions: Ca(NO_3)_2.
5. Verify that the formula reflects the correct ratio of ions and that the overall charge is zero, confirming the compound is neutral.