Redox

• What is the oxidation state of an element?

  0
• What does the oxidation states add up to in a neutral compound?

  0
• What do the oxidation states add up to in an ion?

  the charge of the ion
• What is the oxidation state of a G1 element?

  +1
• What is the oxidation state of a G2 element?

  +2
• What is the oxidation state of a G13 element?

  +3
• What is the oxidation state of fluorine?

  -1
• When does the oxidation of hydrogen change to -1?

  with only metals
• When does the oxidation state of Oxygen change to +2?

  When with F
• When does the oxidation state of Oxygen change to -1?

  in peroxides
• When does the oxidation state of chlorine change to a positive value?

  with O or F
• What do roman numerals represent?

  the positive oxidation state of an element that can have more than one oxidation state e.g. transition metals
• Oxidation is?

  Gain of= oxygen

  Loss of= electrons

  Oxidation state= increases
• Reduction is?

  Loss of= oxygen

  Gain of= electrons

  Oxidation state= decreases
• Write the half equation for K?

  K + e- --> K+
• Metals tend to undergo oxidation. They lose electrons forming positive ions. Their oxidation number increases.
• Non-metals tend to undergo reduction. They gain electrons forming negative ions. Their oxidation state decreases.
• what are the products when an acid reacts with a metal?

  salt + hydrogen
• What is the test for hydrogen?

  lit splint =squeaky pop sound
• What is observed when Mg reacts with HCl?

  Mg dissolves, effervesence, temperature increase
• Mg reacts with H2SO4. Write the equation, oxidation states and what has been reduced and oxidised?

  Mg + H2SO4 --> MgSO4 + H2

  0 +1,+6,-2 +2,+6,-2 0

  Mg oxidised 0 to +2

  H reduced +1 to 0