What is the oxidation number of Mg in elemental magnesium (Mg)?

• A. +2
• B. +1
• C. 0
• D. -2

Answer: (C)

Verified step by step guidance

1. Recall that the oxidation number of an element in its elemental (pure) form is always zero. This is because it is not combined with any other element and thus has no charge imbalance.
2. Identify that magnesium (Mg) in this problem is in its elemental form, meaning it is just Mg atoms by themselves, not bonded to other elements.
3. Apply the rule: For any pure element, the oxidation number is 0. Therefore, the oxidation number of Mg in elemental magnesium is 0.
4. Understand that oxidation numbers indicate the hypothetical charge an atom would have if all bonds were ionic, but since elemental Mg is not bonded, it remains neutral.
5. Conclude that the correct oxidation number for Mg in elemental magnesium is 0, not +2, +1, or -2.