Which of the following is the correct chemical formula for magnesium oxide?

• A. Mg_2O_3
• B. Mg_2O
• C. MgO
• D. MgO_2

Answer: (C)

Verified step by step guidance

1. Identify the charges of the ions involved: Magnesium (Mg) typically forms a +2 charge (Mg^{2+}), and oxygen (O) typically forms a -2 charge (O^{2-}).
2. To write the correct chemical formula, the total positive charge must balance the total negative charge, resulting in a neutral compound.
3. Since Mg^{2+} and O^{2-} have charges of equal magnitude but opposite sign, they combine in a 1:1 ratio to balance the charges.
4. Write the formula by placing the symbols for magnesium and oxygen with no subscripts (or a subscript of 1) because one Mg^{2+} ion balances one O^{2-} ion, giving MgO.
5. Verify that the formula is electrically neutral by confirming that the sum of the charges is zero: (+2) + (-2) = 0, confirming MgO is the correct formula.