Which of the following is the correct name for the compound formed when potassium reacts with sulfur?

• A. Potassium sulfur
• B. Potassium sulfate
• C. Potassium disulfide
• D. Potassium sulfide

Answer: (D)

Verified step by step guidance

1. Identify the elements involved in the compound: potassium (K) and sulfur (S).
2. Determine the charges of the ions formed by each element: potassium typically forms a +1 ion (K\^+), and sulfur typically forms a -2 ion (S\^{2-}).
3. Balance the total positive and negative charges to form a neutral compound. Since potassium has a +1 charge and sulfur has a -2 charge, two potassium ions are needed to balance one sulfur ion, resulting in the formula K\_2S.
4. Name the compound by combining the metal name (potassium) with the nonmetal root name (sulf-) and adding the suffix '-ide' to the nonmetal, giving 'potassium sulfide'.
5. Confirm that the name matches the correct ionic compound naming conventions, which do not use prefixes for ionic compounds and do not include 'sulfate' (which is a polyatomic ion SO\_4\^{2-}) or 'disulfide' (which implies a covalent compound with two sulfur atoms).