Which of the following is the correct chemical formula for the ionic compound formed between barium (Ba) and sulfur (S)?

• A. Ba2S2
• B. BaS2
• C. Ba2S
• D. BaS

Answer: (D)

Verified step by step guidance

1. Identify the charges of the ions formed by barium and sulfur. Barium (Ba) is an alkaline earth metal in Group 2, so it typically forms a +2 cation: \(\mathrm{Ba^{2+}}\). Sulfur (S) is a nonmetal in Group 16 and typically forms a -2 anion: \(\mathrm{S^{2-}}\).
2. Determine the ratio of ions needed to balance the overall charge of the compound. Since barium has a +2 charge and sulfur has a -2 charge, one \(\mathrm{Ba^{2+}}\) ion will balance with one \(\mathrm{S^{2-}}\) ion to make a neutral compound.
3. Write the chemical formula by combining the ions in the ratio that balances the charges. Because the charges are equal and opposite, the formula is simply \(\mathrm{BaS}\), with one barium ion and one sulfur ion.
4. Check the other options to confirm they do not represent the simplest whole-number ratio of ions. For example, \(\mathrm{Ba_2S_2}\) can be simplified to \(\mathrm{BaS}\), and \(\mathrm{BaS_2}\) or \(\mathrm{Ba_2S}\) do not balance the charges correctly.
5. Conclude that the correct chemical formula for the ionic compound formed between barium and sulfur is \(\mathrm{BaS}\), reflecting the 1:1 ratio of \(\mathrm{Ba^{2+}}\) to \(\mathrm{S^{2-}}\) ions.