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

• A. Ba2NO3
• B. BaNO3
• C. Ba2(NO3)
• D. Ba(NO3)2

Answer: (D)

Verified step by step guidance

1. Identify the ions involved: Barium is a metal from Group 2 and forms a cation with a charge of +2, written as \(\mathrm{Ba^{2+}}\).
2. Nitrate is a polyatomic ion with the formula \(\mathrm{NO_3^-}\) and carries a charge of -1.
3. To write the correct formula for barium nitrate, balance the total positive and negative charges so the compound is electrically neutral.
4. Since barium has a +2 charge and nitrate has a -1 charge, you need two nitrate ions to balance one barium ion, resulting in the formula \(\mathrm{Ba(NO_3)_2}\).
5. Use parentheses around the polyatomic ion \(\mathrm{NO_3}\) when more than one is present to indicate that the subscript applies to the entire ion.