What is the oxidation number of magnesium in the compound MgCl_2?

• A. +1
• B. 0
• C. -2
• D. +2

Answer: (D)

Verified step by step guidance

1. Recall that the oxidation number of an element in its elemental form is 0, but in compounds, it depends on the bonding and the other elements present.
2. Identify the common oxidation states of the elements involved: chlorine (Cl) typically has an oxidation number of -1 in compounds.
3. Write the general formula for the compound and set up an equation for the sum of oxidation numbers, which must equal zero for a neutral compound. For MgCl_2, this is: \(x + 2(-1) = 0\), where \(x\) is the oxidation number of magnesium.
4. Solve the equation for \(x\): \(x - 2 = 0\), so \(x = +2\).
5. Conclude that the oxidation number of magnesium in MgCl_2 is +2.