It can mean that the element has lost 2 electrons to form a pos. 2 ion. Or it can mean that in a particular compound (or polyatomic ion) that atom is combined with more electronegative elements in a particular combination that the rules used to assign oxidation numbers gives this atom a +2 oxidation number.
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.
In the compound H2S, hydrogen has an oxidation number of +1, and sulfur has an oxidation number of -2.
-2
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.
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.
Mn increase in oxidation number from +4 to +7.
In the compound H2S, hydrogen has an oxidation number of +1, and sulfur has an oxidation number of -2.
Potassium's minimum oxidation number is zero.Its maximum is plus one.
-2
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.
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
Sulphur has 6 valence electrons. So its maximum oxidation number is +6.
Usually, oxygen has an oxidation of -2 (that is unless in a compound with peroxides or halogens).
The oxidation number of each hydrogen (H) in H3O+ is +1. The oxidation number of oxygen (O) is -2. Overall, the oxidation number of the H3O+ ion is +1.
Hydrogen has an oxidation number of +1 in most of its compounds and -1 in metal hydrides and hydrocarbons.