Which of the following is the correct chemical formula for the ionic compound formed between magnesium (Mg) and sulfur (S) atoms?

• A. Mg2S2
• B. MgS2
• C. MgS
• D. Mg2S

Answer: (C)

Verified step by step guidance

1. Identify the charges of the ions formed by magnesium and sulfur. Magnesium (Mg) typically forms a cation with a charge of +2, written as Mg^{2+}, and sulfur (S) typically forms an anion with a charge of -2, written as S^{2-}.
2. Determine the ratio of ions needed to balance the total positive and negative charges in the compound. Since Mg^{2+} has a +2 charge and S^{2-} has a -2 charge, one Mg^{2+} ion will balance with one S^{2-} ion to achieve electrical neutrality.
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 will have one magnesium ion and one sulfur ion, resulting in MgS.
4. Check the given options against the correct formula MgS. Mg2S2 can be simplified to MgS, MgS2 implies two sulfur atoms per magnesium which does not balance charges, and Mg2S implies two magnesium atoms per sulfur which also does not balance charges.
5. Conclude that the correct chemical formula for the ionic compound formed between magnesium and sulfur is MgS.