An oxidation number of 3 means that the element has a charge within the compound of +3. For example: AlCl3 (Aluminum chloride). Cl has a charge of -1 because it gains 1 electron during bonding to become stable so Al has to have a charge of +3 to balance the overall charge of the compound to zero.
In KMnO4, Mn has an oxidation number of +7, KNO2 has N with an oxidation number of +3, and H2SO4 has S with an oxidation number of +6. In MnSO4, Mn has an oxidation number of +2, H2O has O with an oxidation number of -2, KNO3 has N with an oxidation number of +5, and K2SO4 has S with an oxidation number of +6.
The oxidation number of hydrogen in NH3 is +1, and the oxidation number of nitrogen is -3. This is because hydrogen typically has an oxidation number of +1 and in compounds, nitrogen usually has an oxidation number of -3.
-2
In the compound Al₂O₃, aluminum has an oxidation number of +3, and oxygen has an oxidation number of -2. This gives a total charge of zero for the compound, as it should be electrically neutral.
In K2MnF6, +1 for K, +4 for Mn and -1 for F In SbF5, +5 for Sb and -1 for F In KSbF6, +1 for K, +5 for Sb and -1 for F In MnF3, +3 for Mn and -1 for F In F2, 0 for F
In KMnO4, Mn has an oxidation number of +7, KNO2 has N with an oxidation number of +3, and H2SO4 has S with an oxidation number of +6. In MnSO4, Mn has an oxidation number of +2, H2O has O with an oxidation number of -2, KNO3 has N with an oxidation number of +5, and K2SO4 has S with an oxidation number of +6.
The oxidation number of hydrogen in NH3 is +1, and the oxidation number of nitrogen is -3. This is because hydrogen typically has an oxidation number of +1 and in compounds, nitrogen usually has an oxidation number of -3.
Each of the hydrogen atoms in H2 has an oxidation number of 0.
-2
Usually, oxygen has an oxidation of -2 (that is unless in a compound with peroxides or halogens).
In the compound Al₂O₃, aluminum has an oxidation number of +3, and oxygen has an oxidation number of -2. This gives a total charge of zero for the compound, as it should be electrically neutral.
In K2MnF6, +1 for K, +4 for Mn and -1 for F In SbF5, +5 for Sb and -1 for F In KSbF6, +1 for K, +5 for Sb and -1 for F In MnF3, +3 for Mn and -1 for F In F2, 0 for F
An example is the ferric ion: Fe(III) or Fe3+.
The oxidation number of Iodine (I) in HIO2 is +3. This is because the sum of the oxidation numbers in a neutral molecule must add up to zero, and since hydrogen is typically assigned an oxidation number of +1, and oxygen is typically assigned an oxidation number of -2, the oxidation number of Iodine is +3.
The oxidation number of Al is +3.
The oxidation number of Al in Al2Br6 is +3. Each bromine atom has an oxidation number of -1, and since the compound is neutral, the sum of the oxidation numbers must equal zero. Hence, each Al atom must have an oxidation number of +3 to balance the -6 from the bromine atoms.
The oxidation number of H in HNO2 is +1, the oxidation number of N is +3, and the oxidation number of O is -2.