Numbers
Edexcel A-Level Chemistry 9CH0
Atomic Structure and the Periodic Table
Bonding and Structure
Inorganic Chemistry and the Periodic Table
Topic overviewFlame tests and how they workThermal decomposition of nitrates and carbonatesCarrying out flame tests and testing the gasesGroup 2 elements and their compoundsTrends in Group 7 and predicting fluorine and astatineHalogen displacement reactionsDisproportionation and the reactions of chlorineHalides with concentrated sulfuric acid, and the hydrogen halidesTesting for halide ions with silver nitrateTesting for carbonate and hydrogencarbonate ionsTesting for sulfate and ammonium ions
Formulae, Equations and Amounts of Substance
Topic overviewThe mole, molar mass and empirical formulaThe ideal gas equation and molar volumeEquations, concentration and reacting quantitiesStandard solutions, titration and uncertaintyPercentage yield, atom economy and acid reactionsCore practicals 1 to 3Empirical formula and water of crystallisation by experimentApparatus, uncertainty and mathematical skills
Organic Chemistry I
Topic overviewFormulae, homologous series and functional groupsIUPAC nomenclatureTypes of organic reaction and structural isomerismStereoisomerism and E/Z nomenclaturePractical techniques in organic chemistryAlkanes, crude oil and combustion pollutantsRadical substitutionAlkenes, the double bond and hydrogenationElectrophilic addition, Markovnikov's rule and the test for an alkeneAddition polymers and waste polymersNucleophilic substitution of halogenoalkanesRates of hydrolysis and the SN1 and SN2 mechanismsClassifying and oxidising alcoholsAlcohols: practical techniques and the core practicals
Modern Analytical Techniques I
Energetics I
Kinetics I
Equilibrium I
Acid-Base Equilibria
Energetics II
Redox II
Transition Metals
Topic overviewElectron configuration and what makes a transition metalComplex ions, ligands and the colour of transition metal ionsCoordination number, monodentate ligands and the shapes of complexesBidentate and multidentate ligands, and ligand exchangeVanadium and chromium chemistryReactions with sodium hydroxide and ammoniaCobalt and copper complexesLigand exchange, amphoteric behaviour and the chelate effectTransition metals as catalysts
Kinetics II
Organic Chemistry II
Topic overviewChiralityAldehydes, ketones and their oxidationReduction and nucleophilic addition of HCNTesting for a carbonyl group: 2,4-DNPH and the iodoform reactionCarboxylic acids and their reactionsEsters and acyl chloridesReflux, extraction and recrystallisationDistillation, melting temperature and working safely
Organic Chemistry III
Topic overviewThe structure of benzene and the evidence for itElectrophilic substitution of benzeneNitration, halogenation, Friedel-Crafts and phenolAmines: structure and basicityReactions of amines and preparing themAmides and condensation polymersAmino acids, zwitterions and proteinsEmpirical and molecular formulae from analytical dataGrignard reagents and multi-step synthesisPurification techniques and the aspirin preparation
Redox I
- 2 subtopics
- 8 things to know
- Papers 1, 2 and 3
What Redox I covers
Covers oxidation numbers and the rules for assigning them, the definitions of oxidation and reduction in terms of electrons, disproportionation, and building ionic equations from half-equations.
Where it is assessed
Papers 1, 2 and 3
Core inorganic and physical chemistry, drawn on by both context papers.
Check the Pearson Edexcel specification ↗The 2 subtopics
Each one has its own page.
- Oxidation numbersRecall questions on the rules for assigning oxidation numbers, on working them out in ions and compounds, and on what a Roman numeral in a name means.Open →
- Oxidation, reduction, disproportionation and half-equationsRecall questions on defining oxidation and reduction by electron transfer, identifying oxidising and reducing agents, spotting disproportionation, and combining half-equations.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
How is a full ionic equation built from two half-equations?
Key term
What does a Roman numeral in a name tell you?
Numbers
In Cl₂ + H₂O ⇌ HCl + HClO, give the oxidation numbers of chlorine and explain why this is disproportionation.
Key term
What does an element's oxidation number mean?
Key term
Define oxidation in terms of electrons.
Key term
What is the oxidation number of a simple monatomic ion?
Key term
Define reduction in terms of electrons.
Take Redox I further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Oxidation vs Reduction
Oxidation: electron loss or an increase in oxidation number. Reduction: electron gain or a decrease in oxidation number.
Oxidising agent vs Reducing agent
Oxidising agent: species accepting electrons. Reducing agent: species donating electrons.
Disproportionation vs Comproportionation
Disproportionation: one species undergoing both electron loss and electron gain. Comproportionation: two assigned states forming one intermediate state.
Questions from this topic
Each one with the model answer underneath.
- 1
What does an element's oxidation number mean?
Model answer
The charge an atom would have if all the bonds in the species were treated as fully ionic.
- 2
What is the oxidation number of an atom in an uncombined element?
Model answer
Zero.
- 3
What is the oxidation number of a simple monatomic ion?
Model answer
Equal to the charge on the ion (e.g. Na⁺ is +1, Cl⁻ is -1).
- 4
What is the usual oxidation number of oxygen, and its exceptions?
Model answer
Usually -2; it is -1 in peroxides and +2 in the compound with fluorine (OF₂).
- 5
What is the usual oxidation number of hydrogen, and its exception?
Model answer
Usually +1; it is -1 in metal hydrides such as NaH.
- 6
What is the oxidation number of fluorine in its compounds?
Model answer
Always -1.
What is inside Levo
Six ways to work the same material.
Redox I revision questions
- What does Redox I cover in Edexcel A-Level Chemistry?
- 2 subtopics: oxidation numbers and oxidation, reduction, disproportionation and half-equations. Each one has its own page with questions and model answers.
- How is Redox I organised?
- By the Edexcel 9CH0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Redox I, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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