Oxidation States

• Uncombined Elements


  = 0

  E.G: Cl2. Cl = 0
• Ions

  Same as the charge on ion. E.G: Ca2+. Ca = +2
• Group 1


  Always +1
• Group 2


  Always +2
• Aluminium 


  Always +3
• Hydrogen


  +1 - usually
• Chlorine


  -1
• Fluroine

  Always -1
• Oxygen


  Usually -2