variable oxidation states

• Transition metals have multiple stable ions in different oxidation states
• Vanadium has four main oxidation states, all of which can be easily prepared. Each vanadium ion is a different colour
• Different ions of vanadium can be prepared by successive reduction with zinc in acid solution.
• If the redox potential of a metal ion is a high value:

  The ion is more easily reduced

  The ion is less stable

  the electrode potential is high
• Vanadium species in oxidation states IV, III and II are formed by the reduction of vanadate(V) ions by zinc in acidic solution.
• The redox potential for a transition metal ion changing from a higher to a lower oxidation state is influenced by pH and by the ligand.
• Redox potential refers to how easy it is to reduce a metal
• The redox potential and standard electrode potential will differ if:

  1)The solution's ligands are different

  2)The solution's pH is different