all

• Oxidation state


  The charge on an atom/ion
• The common oxidation states of oxygen are -2
• The common oxidation states of hydrogen are +1
• Oxidation number of metals in compounds

  • Na in NaOH: +1
  • Mg in MgO: +2
  • Al in Al2O3: +3
• Oxidation state of oxygen in H2O2

  • 1
• Oxidation state of hydrogen in metal hydrides

  • 1
• Oxidation state of Fe in FeCl3

  +3
• The chemical formula of a compound containing sulfur with oxidation state +6 and oxygen with oxidation state -2 is SO3
• Reduction

  The gain of electrons by an atom/ion, resulting in the decrease of the oxidation number
• Oxidation

  The loss of electrons by an atom/ion, resulting in the increase of the oxidation number
• Reducing agent

  The species which brings about reduction by donating electrons to the species being reduced
• Oxidising agent

  The species which brings about oxidation by gaining electrons from the species being oxidised
• Redox reaction

  A reaction in which oxidation and reduction occur in different species simultaneously
• Balancing two half equations

  Write the two half equations

  2. Balance the number of electrons transferred

  3. Combine the balanced half equations
• First ionisation energy decreases down Groups 1 and 2


  More electron shells and greater atomic radius increases shielding, reducing nuclear attraction on outer electrons
• Reactivity increases down Group 1 from Li to K


  Increasing atomic radius and shielding makes it easier to lose the outer electron to form a 1+ ion
• Reactivity increases down Group 2 from Mg to Ba


  Increasing atomic radius and shielding makes it easier to lose the two outer electrons to form a 2+ ion
• The products of the reaction between lithium and water are lithium hydroxide and hydrogen
• The chemical equation for the reaction between sodium and water is 2Na + 2H2O → 2NaOH + H2
• The product formed when potassium reacts with oxygen is potassium oxide
• The chemical equation for the reaction between lithium and oxygen is 4Li + O2 → 2Li2O
• When Group 1 elements react with chlorine, metal chlorides are formed (e.g. NaCl)
• When Group 2 elements react with oxygen, the general equation is 2X + O2 → 2XO, where X is the Group 2 element
• When Group 2 elements react with water, the general equation is X + 2H2O → X(OH)2 + H2, where X is the Group 2 element
• When Group 2 elements react with chlorine, the general equation is X + Cl2 → XCl2, where X is the Group 2 element
• When a Group 2 or Group 1 hydroxide/oxide reacts with a dilute acid, a salt and water are produced
• The chemical equation for the reaction between sodium hydroxide and dilute hydrochloric acid is NaOH + HCl → NaCl + H2O
• The chemical equation for the reaction between magnesium hydroxide and dilute sulfuric acid is Mg(OH)2 + H2SO4 → MgSO4 + 2H2O
• What is produced when a Group 2 or Group 1 hydroxide/oxide reacts with a dilute acid?

  Salt and water
• Chemical equation for the reaction between sodium hydroxide and dilute hydrochloric acid

  NaOH + HCl → NaCl + H2O
• Chemical equation for the reaction between magnesium hydroxide and dilute sulfuric acid

  Mg(OH)2 + H2SO4 → MgSO4+ 2H2O
• Chemical equation for the reaction between lithium oxide and dilute sulfuric acid

  Li2O + H2SO4 → Li2SO4 + H2O
• Chemical equation for the reaction between barium oxide and dilute hydrochloric acid

  BaO + 2HCl → BaCl2 + H2O
• What is produced when Group 1 and 2 oxides react with water?

  Metal Hydroxides
• Chemical equation for the reaction between calcium oxide and water

  CaO + H2O → Ca(OH)2
• Trend in solubility of Group 2 hydroxides down the group

  • The solubility of Group 2 hydroxides increases down the group.
• Trend in solubility of Group 2 sulfates down the group

  • The solubility of Group 2 sulfates decreases down the group.
• Trend in thermal stabilities of Group 1 and 2 carbonates

  • The thermal stabilities of Group 1 and 2 carbonates increase down the group.
• Trend in thermal stabilities of Group 1 and 2 nitrates

  • The thermal stabilities of Group 1 and 2 nitrates increase down the group.
• Why do the thermal stabilities of carbonates and nitrates increase down Groups 1 and 2?

  
  

  Down the groups, the ionic radii increase while the magnitude of the charge remains the same. Therefore, the charge densities of the group 1 and 2 ions decrease. As the ions have less charge density, they distort the Carbonate and nitrate ions less, so the compounds take more energy to break.