Which of the following is the correct chemical formula for a compound composed of aluminum ions and sulfate ions?

• A. Al2(SO4)3
• B. Al(SO4)3
• C. Al3(SO4)2
• D. AlSO4

Answer: (A)

Verified step by step guidance

1. Identify the charges of the ions involved: aluminum ion is typically Al^{3+} and sulfate ion is SO_4^{2-}.
2. Determine the ratio of ions needed to balance the total positive and negative charges so that the compound is electrically neutral.
3. Set up the charge balance equation: 3 times the charge of aluminum ions plus 2 times the charge of sulfate ions should equal zero, i.e., 3(+3) + 2(-2) = 0.
4. From the charge balance, deduce the formula by combining 2 aluminum ions with 3 sulfate ions, resulting in Al_2(SO_4)_3.
5. Write the chemical formula with the correct subscripts to reflect the number of each ion in the compound: Al_2(SO_4)_3.