Redox

• OIL RIG

  oxidation is loss of electrons

  reduction is gain of electrons
• Reducing agents

  Lose electrons and are oxidised themselves
• Oxidising agent

  Gain electrons and are reduced themselves
• Oxidation numbers - uncombined elements


  Always 0 eg Cl2 , fe
• Oxidation numbers - ions

  Same as charge on ion
• Oxidation numbers - group 1

  Always +1
• Oxidation numbers- group 2

  Always 2+
• Oxidation numbers - aluminium

  Always +3
• Oxidation numbers - hydrogen

  1+

  Except in hydrides (metal bonded with hydrogen ) = -1
• Oxidation numbers -chlorine

  -1

  Except if in a compound with F and O it would have a positive value
• Oxidation numbers - fluorine

  Always -1
• Oxidation numbers- oxygen

  -2

  except if it's in peroxides

  +2 in OF2
• Oxidation states - transition metals


  Variable oxidation states
• Metals and redox

  When metals react with acids they are oxidised and form a salt and hydrogen gas