If magnesium and nitrogen react to form a neutral compound, what is the molecular formula of the product?

• A. MgN2
• B. Mg3N2
• C. MgN
• D. Mg2N3

Answer: (B)

Verified step by step guidance

1. Identify the charges of the ions formed by magnesium and nitrogen. Magnesium typically forms a Mg^{2+} ion, and nitrogen typically forms an N^{3-} ion.
2. Determine the ratio of magnesium ions to nitrogen ions needed to balance the total positive and negative charges so that the compound is electrically neutral.
3. Set up the charge balance equation: (number of Mg^{2+} ions) \times (+2) + (number of N^{3-} ions) \times (-3) = 0.
4. Find the smallest whole number ratio of Mg^{2+} to N^{3-} ions that satisfies the charge balance. This involves finding the least common multiple of the charges 2 and 3.
5. Write the molecular formula using the ratio found, placing the number of each ion as subscripts after the element symbols, resulting in Mg_{3}N_{2}.