Which of the following is the correct formula for the ionic compound formed between magnesium and chlorine?

• A. Mg_2Cl
• B. Mg_2Cl_2
• C. MgCl_2
• D. MgCl

Answer: (C)

Verified step by step guidance

1. Identify the charges of the ions formed by magnesium and chlorine. Magnesium typically forms a \(\text{Mg}^{2+}\) ion, and chlorine forms a \(\text{Cl}^{-}\) ion.
2. Determine the ratio of ions needed to balance the total positive and negative charges so that the compound is electrically neutral.
3. Since magnesium has a charge of +2 and chlorine has a charge of -1, you need two chloride ions to balance one magnesium ion.
4. Write the formula by placing the magnesium ion first, followed by the number of chloride ions needed, which is two, resulting in \(\text{MgCl}_2\).
5. Verify that the total positive charge (+2 from one \(\text{Mg}^{2+}\)) equals the total negative charge (2 × -1 from two \(\text{Cl}^{-}\) ions), confirming the compound is neutral.