1.07 redox

• in terms of electrons what is oxidation?

  loss of electrons.
• in terms of electrons what is reduction?

  the gain of electrons.
• electrons are only transferred when what happens?

  reduction and oxidation.
• what is a reducing agent?

  a substance which reduces another (donating electrons) therefore being oxidised itself.
• what is an oxidising agent?

  a substance which oxidises another (accepting electrons) therefore being reduced itself.
• what is the oxidation state of uncombined elements?

  0
• what is the oxidation state of an ion?


  the charge of the ion.
• what is the oxidation number on group one elements?

  +1
• what is the oxidation number of group 2 elements?

  +2
• what is the oxidation number of aluminium?

  +3
• what is the oxidation number of hydrogen?

  +1 unless it is combined with a metal (in a hydride) in which case it is -1.
• what is the oxidation state of chlorine?

  -1 unless in a compound with fluorine or oxygen then it will be positive.
• what is the oxidation number of fluorine?

  -1
• what is the oxidation number of oxygen?

  -2 unless in a peroxide (X2O2) then it is -1 and unless it is in OF2 specifically then it is +2.
• what is the oxidation number of a total compound?

  0
• what is reduction in terms of oxidation number?

  decrease in oxidation number.
• what is oxidation in terms of oxidation number?

  increase in oxidation number.
• what are the steps to balancing half equations?

  write the species before and after a reaction. balance any atoms apart from oxygen and hydrogen. balance any oxygens with H2O.balance any hydrogens with H+.