SPM Chemistry

Oxidation Number and IUPAC Nomenclature

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Using the Oxidation States in Naming Compounds

  1. You will have come across names like iron(II) sulphate and iron(III) chloride. The (II) and (III) are the oxidation states of the iron in the two compounds: +2 and +3 respectively. That tells you that they contain Fe2+ and Fe3+ ions. Example

    Formula

    		 Name of the compound
    FeCl2 Iron(II) chloride
    FeCl3 Iron (III) chloride
    MnO2 Manganese(IV) oxide
    Mn(NO3)2 Manganese (II) nitrate
    PbCl2 Lead(II) chloride
  2. Transition metals always show difference oxidation state as shown in the table below.

    Metal

    Oxidation state
    Fe +2, +3
    Cu +1, +2
    Mn +2, +4, +6, +7
  3. Non-metal elements (except fluorine) usually have more than one oxidation state.