Reactivity 3.2 Electron transfer reactions
Reactivity 3.2.1
Understandings:
  • Oxidation and reduction can be described in terms of electron transfer, change in oxidation state, oxygen gain/loss or hydrogen loss/gain.
Learning outcomes:
  • Deduce oxidation states of an atom in a compound or an ion.
  • Identify the oxidized and reduced species and the oxidizing and reducing agents in a chemical reaction.
Additional notes:
  • Include examples to illustrate the variable oxidation states of transition element ions and of most main group non-metals.
  • Include the use of oxidation numbers in the naming of compounds.
Linking questions:
  • Structure 3.1 What are the advantages and limitations of using oxidation states to track redox changes?
  • Structure 2.3 The surface oxidation of metals is often known as corrosion. What are some of the consequences of this process?
This video covers the definitions of oxidation and reduction. 
Reactivity 3.2.2
Understandings:
  • Half-equations separate the processes of oxidation and reduction, showing the loss or gain of electrons.
Learning outcomes:
  • Deduce redox half-equations and equations in acidic or neutral solutions.​
This video covers how to balance redox equations in acidic solution.
Reactivity 3.2.3
Understandings:
  • The relative ease of oxidation and reduction of an element in a group can be predicted from its position in the periodic table.
  • The reactions between metals and aqueous metal ions demonstrate the relative ease of oxidation of different metals.
Learning outcomes:
  • Predict the relative ease of oxidation of metals.
  • Predict the relative ease of reduction of halogens.
  • Interpret data regarding metal and metal ion reactions.
Additional notes:
  • The relative reactivity of metals observed in metal/ metal ion displacement reactions does not need to be learned; appropriate data will be supplied in examination questions.
Linking questions:
  • Structure 3.1 Why does metal reactivity increase, and non-metal reactivity decrease, down the main groups of the periodic table?
This video covers displacement reactions. 
Reactivity 3.2.4
Understandings:
  • Acids react with reactive metals to release hydrogen.
Learning outcomes:
  • Deduce equations for reactions of reactive metals with dilute HCl and H2SO4. ​
This video covers the reactions of acids with reactive metals. 
Reactivity 3.2.5
Understandings:
  • Oxidation occurs at the anode and reduction occurs at the cathode in electrochemical cells.
Learning outcomes:
  • Label electrodes as anode and cathode, and identify their signs/polarities in voltaic cells and electrolytic cells, based on the type of reaction occurring at the electrode.​
This video is an introduction to electrochemical cells. 
Reactivity 3.2.6
Understandings:
  • A primary (voltaic) cell is an electrochemical cell that converts energy from spontaneous redox reactions to electrical energy.
Learning outcomes:
  • Explain the direction of electron flow from anode to cathode in the external circuit, and ion movement across the salt bridge.
Additional notes:
  • Construction of primary cells should include: half- cells containing metal/metal ion, anode, cathode, electric circuit, salt bridge.
Linking questions:
  • Reactivity 1.3 Electrical energy can be derived from the combustion of fossil fuels or from electrochemical reactions. What are the similarities and differences in these reactions?
This video covers voltaic cells. 
Reactivity 3.2.7
Understandings:
  • Secondary (rechargeable) cells involve redox reactions that can be reversed using electrical energy.
Learning outcomes:
  • Deduce the reactions of the charging process from given electrode reactions for discharge, and vice versa.
Additional notes:
  • Include discussion of advantages and disadvantages of fuel cells, primary cells and secondary cells.
Linking questions:
  • Reactivity 2.3 Secondary cells rely on electrode reactions that are reversible. What are the common features of these reactions?
This video covers secondary cells. 
Reactivity 3.2.8
Understandings:
  • An electrolytic cell is an electrochemical cell that converts electrical energy to chemical energy by bringing about non-spontaneous reactions.
Learning outcomes:
  • Explain how current is conducted in an electrolytic cell.
    Deduce the products of the electrolysis of a molten salt.
Additional notes:
  • Construction of electrolytic cells should include: DC power source connected to anode and cathode, electrolyte.
Linking questions:
  • Structure 2.1 Under what conditions can ionic compounds act as electrolytes?
This video covers electrolytic cells. 
Reactivity 3.2.9
Understandings:
  • Functional groups in organic compounds may undergo oxidation.
Learning outcomes:
  • Deduce equations to show changes in the functional groups during oxidation of primary and secondary alcohols, including the two-step reaction in the oxidation of primary alcohols.
Additional notes:
  • Include explanation of the experimental set-up for distillation and reflux.
  • Include the fact that tertiary alcohols are not oxidized under similar conditions.
  • Names and formulas of specific oxidizing agents and the mechanism will not be assessed.
Linking questions:
  • Structure 3.2 How does the nature of the functional group in a molecule affect its physical properties, such as boiling point?
  • Reactivity 1.3 What is the difference between combustion and oxidation of an alcohol?
This video covers the reactions of the alcohols. 
Reactivity 3.2.10
Understandings:
  • Functional groups in organic compounds may undergo reduction.
Learning outcomes:
  • Deduce equations to show reduction of carboxylic acids to primary alcohols via the aldehyde, and reduction of ketones to secondary alcohols.
Additional notes:
  • Include the role of hydride ions in the reduction reaction.
  • Names and formulas of specific reducing agents and the mechanisms will not be assessed.
Linking questions:
  • Structure 3.1 How can oxidation states be used to show that the following molecules are given in increasing order of oxidation: CH4, CH3OH, HCHO, HCOOH, CO2?
This video covers the reduction of carboxylic acids and ketones.
Reactivity 3.2.11
Understandings:
  • Reduction of unsaturated compounds by the addition of hydrogen lowers the degree of unsaturation.
Learning outcomes:
  • Deduce the products of the reactions of hydrogen with alkenes and alkynes.​
Linking questions:
  • Reactivity 3.4 Why are some reactions of alkenes classified as reduction reactions while others are classified as electrophilic addition reactions?
Video coming soon