To determine the oxidation number of manganese (Mn) in the compounds MnI₂ and MnO₂, we can analyze each compound based on the known oxidation states of the other elements involved.
-
MnI₂:
- Iodine (I) typically has an oxidation number of -1.
- In MnI₂, there are two iodine atoms, contributing a total of -2 (2 × -1).
- Let the oxidation number of manganese be x.
- The overall charge of the compound is neutral (0), so we can set up the equation: \[ x + (2 \times -1) = 0 \] \[ x - 2 = 0 \] \[ x = +2 \]
- Therefore, the oxidation number of Mn in MnI₂ is +2.
-
MnO₂:
- Oxygen (O) typically has an oxidation number of -2.
- In MnO₂, there are two oxygen atoms, contributing a total of -4 (2 × -2).
- Let the oxidation number of manganese be y.
- Again, the overall charge of the compound is neutral (0): \[ y + (2 \times -2) = 0 \] \[ y - 4 = 0 \] \[ y = +4 \]
- Therefore, the oxidation number of Mn in MnO₂ is +4.
Putting this all together:
- MnI₂: +2
- MnO₂: +4
Thus, the correct statement is: Manganese has an oxidation number of +2 in MnI₂ and +4 in MnO₂.