Source: https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-5-variable-oxidation-states-a2-only

[Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [A Level](https://senecalearning.com/en-gb/revision-notes/a-level.md) › [Chemistry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry.md) › [AQA](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa.md) › Variable Oxidation States (A2 Only)

# Variable Oxidation States (A2 Only)

Chemistry: AQA A Level, topic 4.2.5

## Oxidation States of Vanadium

Transition metals have multiple stable ions in different oxidation states. For example, vanadium has four main oxidation states, all of which can be easily prepared. Each vanadium ion is a different colour:

### Vanadium (V) - yellow

![Vanadium (V) - yellow](https://image-v2.cdn.app.senecalearning.com/2018-09/ad5c4196-deec-435f-b48b-84e7565b2b5b/yellow-colour%20(1).png)

### Vanadium (IV) - blue

![Vanadium (IV) - blue](https://image-v2.cdn.app.senecalearning.com/2018-09/bd396fa7-c7dd-446e-8a47-7c513da06e74/blue-colour.png)

### Vanadium (III) - green

![Vanadium (III) - green](https://image-v2.cdn.app.senecalearning.com/2018-09/6c9dc5a0-345b-4507-8116-c8f54fe03230/green-colour.png)

### Vanadium (II) - violet

![Vanadium (II) - violet](https://image-v2.cdn.app.senecalearning.com/2018-09/3975cbed-a7a6-4216-af9c-deb04c276ca2/violet-colour.png)

## Vanadium Ion Synthesis

Here we shall look into preparing various oxidation states of vanadium.

### Preparation of vanadium ions

![Preparation of vanadium ions](https://image-v2.cdn.app.senecalearning.com/2018-03/5e28b3d9-024e-4e00-b326-15e3f5221c28/shutterstock_177901814.jpg)

- Different ions of vanadium can be prepared by successive reduction with zinc in acid solution.
- Zinc will donate two electrons to vanadium, so to move vanadium down one oxidation state you add half as much zinc as you have vanadium.
 - The equations for each reduction are on the next slides.

### Vanadium(V) → vanadium(IV)

![Vanadium(V) → vanadium(IV)](https://image-v2.cdn.app.senecalearning.com/2018-09/e27ff672-6109-4c60-8c9f-ae4cebde6609/yellow%20-%20blue.png)

- Vanadium(V) exists as the vanadate ion, VO2+.
- The reduction equation is:
 - 2VO2+(aq) + Zn(s) + 4H+(aq) → Zn2+(aq) + 2VO2+(aq) + 2H2O(l)
 - There is a colour change from yellow to blue.

### Vanadium(IV) → vanadium(III)

![Vanadium(IV) → vanadium(III)](https://image-v2.cdn.app.senecalearning.com/2018-09/66e02936-509e-4794-8ba6-e1bedb31e436/blue%20-%20green%20(1).png)

- The reduction equation is:
 - 2VO2+(aq) + Zn(s) + 4H+(aq) → Zn2+(aq) + 2V3+(aq) + 2H2O(l)
 - There is a colour change from blue to green.

### Vanadium(III) → vanadium(II)

![Vanadium(III) → vanadium(II)](https://image-v2.cdn.app.senecalearning.com/2018-09/de5c6a05-4404-4013-99bb-4822f3dd400c/green-violet.png)

- The reduction equation is: 
 - 2V3+(aq) + Zn(s) → Zn2+(aq) + 2V2+(aq)
 - There is a colour change from green to violet.

## Redox Potentials

Redox potentials give information about the stability of a complex. They are dependent on many factors.

### Redox potentials

![Redox potentials](https://image-v2.cdn.app.senecalearning.com/2018-07/defbb241-d8e9-4b3a-83d3-821f2c90cda2/Electrochemical%20series.jpg)

- Redox potentials show you how easy a metal can be reduced.
 - A redox potential is just another name for an electrode potential.
- Higher values mean the ion is less stable and more easily reduced.
- Standard redox potentials are quoted relative to a standard hydrogen electrode and under standard conditions.

### Differences to standard potentials

![Differences to standard potentials](https://image-v2.cdn.app.senecalearning.com/2018-08/2f758112-5f93-4129-b350-6c97704ed568/terms-conditions-glass-.jpg)

- A redox potential is not always the same as a standard electrode potential.
 - To change a redox potential from the standard electrode potential, you change the conditions.
- In particular, redox potentials can depend on:
 - Ligands.
 - pH.

### Ligands

![Ligands](https://image-v2.cdn.app.senecalearning.com/2018-09/20059925-e3b9-4476-b2ee-236bcd04c698/ligand-complex-transition-metal.png)

- Standard redox potentials are measured in aqueous solution.
 - Changing the ligands will alter the redox potential depending on the bond strength to the metal.

### pH

![pH](https://image-v2.cdn.app.senecalearning.com/courseImages/chemistry/Edexcel/5%20Acids,%20Alkalis,%20pH/universal_indicator.jpg)

- Certain potentials involve H+.
- If the concentration of H+ is changed, the redox potential will change.
 - Usually, a higher concentration of H+ means a higher redox potential.

## Test yourself on Variable Oxidation States (A2 Only)

- How many main oxidation states does vanadium have?
- Which vanadium ion is blue?
- What is a good metal to use to prepare different oxidation states of vanadium?
- Which of the following best describes a redox potential?
- A higher concentration of H+ ions usually means what?

[Practise this topic for free](https://app.senecalearning.com/classroom/course/89dad2dd-9f68-460c-9247-131aea534bdb/section/137fc4f1-37df-45da-83e9-47542d445ec7/session)

- Previous topic: [4.2.4 Colours of Ions (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-4-colours-of-ions-a2-only.md)
- Next topic: [4.2.6 Titrations (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-6-titrations-a2-only.md)

## Chemistry: AQA A Level contents

### 1 Physical Chemistry
- 1.1 Atomic Structure
  - [1.1.1 Fundamental Particles](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-1-fundamental-particles.md)
  - [1.1.2 Isotopes & Mass Number](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-2-isotopes-and-mass-number.md)
  - [1.1.3 Mass Spectrometry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-3-mass-spectrometry.md)
  - [1.1.4 Electron Shells, Sub-Shells & Orbitals](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-4-electron-shells-sub-shells-and-orbitals.md)
  - [1.1.5 Electron Configuration](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-5-electron-configuration.md)
  - [1.1.6 Ionisation Energy](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-6-ionisation-energy.md)
  - [1.1.7 Factors Affecting Ionisation Energies](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-7-factors-affecting-ionisation-energies.md)
  - [1.1.8 Trends of Ionisation](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-8-trends-of-ionisation.md)
  - [1.1.9 Specific Impacts on Ionisation Energies](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-9-specific-impacts-on-ionisation-energies.md)
  - [1.1.10 End of Topic Test - Atomic Structure](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-10-end-of-topic-test-atomic-structure.md)
  - [1.1.11 A-A* (AO3/4) - Atomic Structure](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-1-11-a-a-ao34-atomic-structure.md)
- 1.2 Amount of Substance
  - [1.2.1 Relative Masses](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-1-relative-masses.md)
  - [1.2.2 The Mole](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-2-the-mole.md)
  - [1.2.3 The Ideal Gas Equation](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-3-the-ideal-gas-equation.md)
  - [1.2.4 Empirical & Molecular Formulae](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-4-empirical-and-molecular-formulae.md)
  - [1.2.5 Balanced Equations](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-5-balanced-equations.md)
  - [1.2.6 Percentage Yield](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-6-percentage-yield.md)
  - [1.2.7 A-A* (AO3/4) - Percentage Yield](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-7-a-a-ao34-percentage-yield.md)
  - [1.2.8 Atom Economy](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-8-atom-economy.md)
  - [1.2.9 End of Topic Test - Amount of Substance](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-9-end-of-topic-test-amount-of-substance.md)
  - [1.2.10 A-A* (AO3/4) - Substances & Yield](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-10-a-a-ao34-substances-and-yield.md)
  - [1.2.11 Diagnostic Misconceptions - Moles](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-2-11-diagnostic-misconceptions-moles.md)
- 1.3 Bonding
  - [1.3.1 Ionic Bonding](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-1-ionic-bonding.md)
  - [1.3.2 Covalent & Dative Bonding](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-2-covalent-and-dative-bonding.md)
  - [1.3.3 Carbon Structures](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-3-carbon-structures.md)
  - [1.3.4 Metallic Bonding](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-4-metallic-bonding.md)
  - [1.3.5 Physical Properties](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-5-physical-properties.md)
  - [1.3.6 Shapes of Molecules](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-6-shapes-of-molecules.md)
  - [1.3.7 Polarity](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-7-polarity.md)
  - [1.3.8 Intermolecular Forces](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-8-intermolecular-forces.md)
  - [1.3.9 Intermolecular Forces 2](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-9-intermolecular-forces-2.md)
  - [1.3.10 End of Topic Test - Bonding](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-10-end-of-topic-test-bonding.md)
  - [1.3.11 Exam-Style Question - Shape of Molecules](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-11-exam-style-question-shape-of-molecules.md)
  - [1.3.12 A-A* (AO3/4) - Bonding](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-12-a-a-ao34-bonding.md)
  - [1.3.13 Diagnostic Misconceptions - Ions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-13-diagnostic-misconceptions-ions.md)
  - [1.3.14 Diagnostic Misconceptions - Ionic & Covalent](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-14-diagnostic-misconceptions-ionic-and-covalent.md)
  - [1.3.15 Diagnostic Misconceptions - Phase Change](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-15-diagnostic-misconceptions-phase-change.md)
  - [1.3.16 Diagnostic Misconceptions - Boiling](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-16-diagnostic-misconceptions-boiling.md)
  - [1.3.17 Diagnostic Misconceptions - Polar Bonds](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-3-17-diagnostic-misconceptions-polar-bonds.md)
- 1.4 Energetics
  - [1.4.1 Enthalpy Changes](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-1-enthalpy-changes.md)
  - [1.4.2 Bond Breaking and Making](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-2-bond-breaking-and-making.md)
  - [1.4.3 Enthalpy Changes: Standard Conditions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-3-enthalpy-changes-standard-conditions.md)
  - [1.4.4 Calorimetry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-4-calorimetry.md)
  - [1.4.5 Hess' Law](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-5-hess-law.md)
  - [1.4.6 Bond Enthalpies](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-6-bond-enthalpies.md)
  - [1.4.7 End of Topic Test - Energetics](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-7-end-of-topic-test-energetics.md)
  - [1.4.8 Diagnostic Misconceptions - Calorimetry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-4-8-diagnostic-misconceptions-calorimetry.md)
- 1.5 Kinetics
  - [1.5.1 Collision Theory](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-5-1-collision-theory.md)
  - [1.5.2 Maxwell-Boltzmann Distribution](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-5-2-maxwell-boltzmann-distribution.md)
  - [1.5.3 Increasing Rates](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-5-3-increasing-rates.md)
  - [1.5.4 End of Topic Test - Kinetics](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-5-4-end-of-topic-test-kinetics.md)
- 1.6 Equilibria
  - [1.6.1 Le Chatelier](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-6-1-le-chatelier.md)
  - [1.6.2 Equilibrium Constants](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-6-2-equilibrium-constants.md)
  - [1.6.3 A-A* (AO3/4) - Energetics, Kinetics, Equilibria](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-6-3-a-a-ao34-energetics-kinetics-equilibria.md)
  - [1.6.4 End of Topic Test - Equilibria](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-6-4-end-of-topic-test-equilibria.md)
  - [1.6.5 Diagnostic Misconceptions - Solids](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-6-5-diagnostic-misconceptions-solids.md)
- 1.7 Redox
  - [1.7.1 Redox](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-7-1-redox.md)
  - [1.7.2 End of Topic Test - Redox](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/1-7-2-end-of-topic-test-redox.md)

### 2 Physical Chemistry 2 (A2 Only)
- 2.1 Thermodynamics (A2 Only)
  - [2.1.1 Born-Haber Cycles (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-1-1-born-haber-cycles-a2-only.md)
  - [2.1.2 Born-Haber Cycle Calculations (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-1-2-born-haber-cycle-calculations-a2-only.md)
  - [2.1.3 Entropy (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-1-3-entropy-a2-only.md)
  - [2.1.4 Free Energy (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-1-4-free-energy-a2-only.md)
  - [2.1.5 End of Topic Test - Thermodynamics](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-1-5-end-of-topic-test-thermodynamics.md)
  - [2.1.6 A-A* (AO3/4) - Thermodynamics](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-1-6-a-a-ao34-thermodynamics.md)
- 2.2 Rate Equations (A2 Only)
  - [2.2.1 Rate Equations (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-1-rate-equations-a2-only.md)
  - [2.2.2 Rate Equations 2 (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-2-rate-equations-2-a2-only.md)
  - [2.2.3 The Arrhenius Equation (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-3-the-arrhenius-equation-a2-only.md)
  - [2.2.4 Experimental Methods for Rates (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-4-experimental-methods-for-rates-a2-only.md)
  - [2.2.5 End of Topic Test - Rate Equations](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-5-end-of-topic-test-rate-equations.md)
  - [2.2.6 Exam-Style Question - Rates](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-6-exam-style-question-rates.md)
  - [2.2.7 A-A* (AO3/4) - Rate Equations](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-2-7-a-a-ao34-rate-equations.md)
- 2.3 The Equilibrium Constant Kp (A2 Only)
  - [2.3.1 Properties of Kp (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-3-1-properties-of-kp-a2-only.md)
- 2.4 Electrochemical Cells (A2 Only)
  - [2.4.1 Electrochemical Cells (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-1-electrochemical-cells-a2-only.md)
  - [2.4.2 Electrochemical Series (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-2-electrochemical-series-a2-only.md)
  - [2.4.3 Commercial Application (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-3-commercial-application-a2-only.md)
  - [2.4.4 End of Topic Test - Kp & Electrochemistry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-4-end-of-topic-test-kp-and-electrochemistry.md)
  - [2.4.5 A-A* (AO3/4) - Electrochemical Cells](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-5-a-a-ao34-electrochemical-cells.md)
  - [2.4.6 Diagnostic Misconceptions - Salt Bridges](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-6-diagnostic-misconceptions-salt-bridges.md)
  - [2.4.7 Diagnostic Misconceptions - Electrode, Electrolyte](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-4-7-diagnostic-misconceptions-electrode-electrolyte.md)
- 2.5 Acids & Bases (A2 Only)
  - [2.5.1 Brønsted-Lowry Acids & Bases (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-1-bronsted-lowry-acids-and-bases-a2-only.md)
  - [2.5.2 pH (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-2-ph-a2-only.md)
  - [2.5.3 The Ionic Product of Water (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-3-the-ionic-product-of-water-a2-only.md)
  - [2.5.4 Weak Acids & Bases (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-4-weak-acids-and-bases-a2-only.md)
  - [2.5.5 pH Curves & Titrations (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-5-ph-curves-and-titrations-a2-only.md)
  - [2.5.6 pH Curves & Titrations 2 (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-6-ph-curves-and-titrations-2-a2-only.md)
  - [2.5.7 Buffer Solutions (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-7-buffer-solutions-a2-only.md)
  - [2.5.8 End of Topic Test - Acids & Bases](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-8-end-of-topic-test-acids-and-bases.md)
  - [2.5.9 Exam-Style Question - Weak Acids](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-9-exam-style-question-weak-acids.md)
  - [2.5.10 A-A* (AO3/4) - Acids & Bases](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-10-a-a-ao34-acids-and-bases.md)
  - [2.5.11 Diagnostic Misconceptions - Ammonia is an Alkali](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-11-diagnostic-misconceptions-ammonia-is-an-alkali.md)
  - [2.5.12 Diagnostic Misconceptions - Water's Neutrality](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-12-diagnostic-misconceptions-waters-neutrality.md)
  - [2.5.13 Diagnostic Misconceptions - Concentrate & Strength](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/2-5-13-diagnostic-misconceptions-concentrate-and-strength.md)

### 3 Inorganic Chemistry
- 3.1 Periodicity & Trends
  - [3.1.1 The Periodic Table](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-1-1-the-periodic-table.md)
  - [3.1.2 Trends in the Periodic Table](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-1-2-trends-in-the-periodic-table.md)
  - [3.1.3 End of Topic Test - Periodicity & Trends](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-1-3-end-of-topic-test-periodicity-and-trends.md)
  - [3.1.4 Diagnostic Misconceptions - Atomic Radius](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-1-4-diagnostic-misconceptions-atomic-radius.md)
- 3.2 Group 2
  - [3.2.1 Group 2 Chemistry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-2-1-group-2-chemistry.md)
  - [3.2.2 End of Topic Test - Group 2](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-2-2-end-of-topic-test-group-2.md)
- 3.3 Group 7
  - [3.3.1 Introduction to Halogens](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-3-1-introduction-to-halogens.md)
  - [3.3.2 Reactions of Halogens](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-3-2-reactions-of-halogens.md)
  - [3.3.3 Chlorine & Chlorate(I)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-3-3-chlorine-and-chloratei.md)
  - [3.3.4 End of Topic Test - Group 7](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-3-4-end-of-topic-test-group-7.md)
  - [3.3.5 Exam-Style Question - Group 7](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-3-5-exam-style-question-group-7.md)
  - [3.3.6 A-A* (AO3/4) - Periodicity, Group 2 & 7](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/3-3-6-a-a-ao34-periodicity-group-2-and-7.md)

### 4 Inorganic Chemistry 2 (A2 Only)
- 4.1 Period 3 (A2 Only)
  - [4.1.1 Period 3 Elements & Oxides (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-1-1-period-3-elements-and-oxides-a2-only.md)
  - [4.1.2 Period 3 Oxides (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-1-2-period-3-oxides-a2-only.md)
  - [4.1.3 End of Topic Test - Period 3](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-1-3-end-of-topic-test-period-3.md)
- 4.2 Transition Metals (A2 Only)
  - [4.2.1 General Properties (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-1-general-properties-a2-only.md)
  - [4.2.2 Substitution Reactions (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-2-substitution-reactions-a2-only.md)
  - [4.2.3 Shapes of Complex Ions (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-3-shapes-of-complex-ions-a2-only.md)
  - [4.2.4 Colours of Ions (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-4-colours-of-ions-a2-only.md)
  - [4.2.5 Variable Oxidation States (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-5-variable-oxidation-states-a2-only.md)
  - [4.2.6 Titrations (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-6-titrations-a2-only.md)
  - [4.2.7 Homogeneous Catalysts (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-7-homogeneous-catalysts-a2-only.md)
  - [4.2.8 Heterogeneous Catalysts (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-8-heterogeneous-catalysts-a2-only.md)
  - [4.2.9 End of Topic Test - Transition Metals](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-9-end-of-topic-test-transition-metals.md)
  - [4.2.10 A-A* (AO3/4) - Transition Metals](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-2-10-a-a-ao34-transition-metals.md)
- 4.3 Reactions of Ions in Aqueous Solutions (A2 Only)
  - [4.3.1 Acidity (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-3-1-acidity-a2-only.md)
  - [4.3.2 Identification (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-3-2-identification-a2-only.md)
  - [4.3.3 End of Topic Test - Reactions of Ions in Solution](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/4-3-3-end-of-topic-test-reactions-of-ions-in-solution.md)

### 5 Organic Chemistry 1
- 5.1 Introduction
  - [5.1.1 Naming Conventions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-1-1-naming-conventions.md)
  - [5.1.2 Mechanism](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-1-2-mechanism.md)
  - [5.1.3 Isomerism](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-1-3-isomerism.md)
  - [5.1.4 End of Topic Test - Introduction to Organic Chem](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-1-4-end-of-topic-test-introduction-to-organic-chem.md)
- 5.2 Alkanes
  - [5.2.1 Fractional Distillation](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-2-1-fractional-distillation.md)
  - [5.2.2 Cracking](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-2-2-cracking.md)
  - [5.2.3 Combustion](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-2-3-combustion.md)
  - [5.2.4 Chlorination](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-2-4-chlorination.md)
  - [5.2.5 End of Topic Test - Alkanes](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-2-5-end-of-topic-test-alkanes.md)
- 5.3 Halogenoalkanes
  - [5.3.1 Substitution Reactions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-3-1-substitution-reactions.md)
  - [5.3.2 Elimination Reactions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-3-2-elimination-reactions.md)
  - [5.3.3 Ozone Depletion](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-3-3-ozone-depletion.md)
  - [5.3.4 End of Topic Test - Halogenoalkanes](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-3-4-end-of-topic-test-halogenoalkanes.md)
- 5.4 Alkenes
  - [5.4.1 Introduction to Alkenes](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-4-1-introduction-to-alkenes.md)
  - [5.4.2 Reactions of Alkenes](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-4-2-reactions-of-alkenes.md)
  - [5.4.3 Polymerisation Reactions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-4-3-polymerisation-reactions.md)
  - [5.4.4 Properties of Polymers](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-4-4-properties-of-polymers.md)
  - [5.4.5 End of Topic Test - Alkenes](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-4-5-end-of-topic-test-alkenes.md)
- 5.5 Alcohols
  - [5.5.1 Production of Alcohols](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-5-1-production-of-alcohols.md)
  - [5.5.2 Oxidation of Alcohols](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-5-2-oxidation-of-alcohols.md)
  - [5.5.3 Oxidation of Alcohols - 2](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-5-3-oxidation-of-alcohols-2.md)
  - [5.5.4 Elimination Reactions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-5-4-elimination-reactions.md)
  - [5.5.5 End of Topic Test - Alcohols](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-5-5-end-of-topic-test-alcohols.md)
  - [5.5.6 Exam-Style Question - Alcohols](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-5-6-exam-style-question-alcohols.md)
- 5.6 Organic Analysis
  - [5.6.1 Reactions](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-6-1-reactions.md)
  - [5.6.2 Reactions 2](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-6-2-reactions-2.md)
  - [5.6.3 Mass Spectrometry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-6-3-mass-spectrometry.md)
  - [5.6.4 Infrared Spectroscopy](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-6-4-infrared-spectroscopy.md)
  - [5.6.5 End of Topic Test - Organic Analysis](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-6-5-end-of-topic-test-organic-analysis.md)
- 5.7 A-A* (AO3/4) - Organic 1
  - [5.7.1 A-A* (AO3/4) - Organic 1](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/5-7-1-a-a-ao34-organic-1.md)

### 6 Organic Chemistry 2 (A2 Only)
- 6.1 Optical Isomerism (A2 Only)
  - [6.1.1 Optical Isomerism (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-1-1-optical-isomerism-a2-only.md)
  - [6.1.2 End of Topic Test - Optical Isomerism](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-1-2-end-of-topic-test-optical-isomerism.md)
- 6.2 Aldehydes & Ketones (A2 Only)
  - [6.2.1 Aldehydes & Ketones (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-2-1-aldehydes-and-ketones-a2-only.md)
  - [6.2.2 End of Topic Test - Aldehydes & Ketones](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-2-2-end-of-topic-test-aldehydes-and-ketones.md)
- 6.3 Carboxylic Acids & Esters (A2 Only)
  - [6.3.1 Acids & Esters (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-3-1-acids-and-esters-a2-only.md)
  - [6.3.2 Acylation (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-3-2-acylation-a2-only.md)
  - [6.3.3 End of Topic Test - Carboxylic Acids & Esters](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-3-3-end-of-topic-test-carboxylic-acids-and-esters.md)
- 6.4 Aromatic Chemistry (A2 Only)
  - [6.4.1 Structure & Reactivity (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-4-1-structure-and-reactivity-a2-only.md)
  - [6.4.2 Reactions of Benzene (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-4-2-reactions-of-benzene-a2-only.md)
  - [6.4.3 End of Topic Test - Aromatic Chemistry](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-4-3-end-of-topic-test-aromatic-chemistry.md)
- 6.5 Amines (A2 Only)
  - [6.5.1 Nature & Preparation of Amines (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-5-1-nature-and-preparation-of-amines-a2-only.md)
  - [6.5.2 Basicity & Nucleophilicity (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-5-2-basicity-and-nucleophilicity-a2-only.md)
  - [6.5.3 End of Topic Test - Amines](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-5-3-end-of-topic-test-amines.md)
- 6.6 Polymers (A2 Only)
  - [6.6.1 Condensation Polymers (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-6-1-condensation-polymers-a2-only.md)
  - [6.6.2 Biodegradability (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-6-2-biodegradability-a2-only.md)
- 6.7 Biological Organic (A2 Only)
  - [6.7.1 Amino Acids (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-7-1-amino-acids-a2-only.md)
  - [6.7.2 Proteins (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-7-2-proteins-a2-only.md)
  - [6.7.3 DNA (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-7-3-dna-a2-only.md)
  - [6.7.4 Anti-Cancer Drugs (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-7-4-anti-cancer-drugs-a2-only.md)
  - [6.7.5 End of Topic Test - Biological Organic](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-7-5-end-of-topic-test-biological-organic.md)
- 6.8 Organic Synthesis (A2 Only)
  - [6.8.1 Organic Synthesis (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-8-1-organic-synthesis-a2-only.md)
  - [6.8.2 Examples of Synthetic Routes (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-8-2-examples-of-synthetic-routes-a2-only.md)
  - [6.8.3 End of Topic Test - Polymers & Organic Synthesis](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-8-3-end-of-topic-test-polymers-and-organic-synthesis.md)
- 6.9 NMR Spectroscopy (A2 Only)
  - [6.9.1 Understanding NMR (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-9-1-understanding-nmr-a2-only.md)
  - [6.9.2 Carbon-13 NMR (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-9-2-carbon-13-nmr-a2-only.md)
  - [6.9.3 Hydrogen-1 NMR (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-9-3-hydrogen-1-nmr-a2-only.md)
  - [6.9.4 Hydrogen-1 NMR 2 (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-9-4-hydrogen-1-nmr-2-a2-only.md)
  - [6.9.5 End of Topic Test - NMR](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-9-5-end-of-topic-test-nmr.md)
- 6.10 Chromatography (A2 Only)
  - [6.10.1 Overview of Chromatography (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-10-1-overview-of-chromatography-a2-only.md)
  - [6.10.2 Thin-Layer Chromatography (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-10-2-thin-layer-chromatography-a2-only.md)
  - [6.10.3 Column Chromatography (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-10-3-column-chromatography-a2-only.md)
  - [6.10.4 Gas Chromatography (A2 Only)](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-10-4-gas-chromatography-a2-only.md)
  - [6.10.5 End of Topic Test - Chromatography](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-10-5-end-of-topic-test-chromatography.md)
- 6.11 A-A* (AO3/4) - Organic 2
  - [6.11.1 A-A* (AO3/4) - Organic 2](https://senecalearning.com/en-gb/revision-notes/a-level/chemistry/aqa/6-11-1-a-a-ao34-organic-2.md)