Numbers
OCR A-Level Chemistry H432
Foundations in Chemistry
Topic overviewAtomic structure, isotopes and counting sub-atomic particlesRelative isotopic, atomic, molecular and formula massPredicting ionic charges and the common ionsWriting formulae, balanced equations and ionic equationsThe mole, molar mass and the Avogadro constantEmpirical and molecular formulae, and hydrated saltsGas volumes, concentration and the ideal gas equationStoichiometry, percentage yield and atom economyApparatus, and why high atom economy mattersMathematical skills and measuring mass, volume and gasAcids, alkalis, dissociation and neutralisationPreparing a standard solutionCarrying out a titration and its calculationsPlanning an experiment: variables, apparatus and recording resultsPractical safety, heating and filtrationUncertainty, percentage error, precision and accuracyEvaluating results: anomalies, conclusions, limitations and improvementsAssigning oxidation numbersRoman numerals in names, and the chlorate and nitrate ionsOxidation, reduction and metals reacting with acidsRedox equations and identifying what is oxidisedShells, orbitals and sub-shellsThe order in which sub-shells fillWriting electron configurations for atoms and ions
Bonding and Structure
Topic overviewIonic bonding and the properties of ionic compoundsCovalent and coordinate bondingLone pairs, bonding pairs and average bond enthalpyElectron pair repulsion theory, linear and trigonal planar shapesTetrahedral, pyramidal and non-linear shapes and their bond anglesOctahedral shapes, ions, and drawing molecules in three dimensionsElectronegativity, polar bonds and polar moleculesPermanent and induced dipoles, and hydrogen bondingSimple molecular lattices and why they melt easilySolubility and conductivity of simple molecular compounds
Periodic Table and Energy
Topic overviewPeriodicity and the electron configurations of periods 2 and 3The blocks, and first and successive ionisation energiesMetallic and giant covalent structures and their propertiesGroup 2 reactions with oxygen, water and acidsIonisation energy down Group 2 and the alkalinity of the hydroxidesUses of Group 2 compounds in agriculture and medicineThe halogens: boiling points, London forces and reactivityHalogen displacement reactions and the colours seenDisproportionation and the chlorination of waterTesting for halide ions with silver nitrate and ammoniaTesting for carbonate, sulfate and halide ionsTesting for ammonium ions and the order of the testsConcentration, pressure and measuring reaction rateCatalysts and their industrial importanceThe Boltzmann distribution, temperature and catalysts
Enthalpy Changes
Topic overviewExothermic and endothermic reactions and enthalpy profilesStandard conditions and the standard enthalpy changesBond enthalpies, q = mcΔT and calorimetryCalculating enthalpy change from bond enthalpiesWhy average bond enthalpies give only an approximationHess' law and enthalpy cycles from combustion and formation dataWorking through an enthalpy cycle and the sign conventionsCalorimetry and correcting for heat loss
Chemical Equilibrium
Basic Concepts of Organic Chemistry
Topic overviewIUPAC nomenclature and the alkyl groupsGeneral, structural, displayed and skeletal formulaeHomologous series, functional groups and saturationStructural isomers, bond fission and curly arrowsChain, position and functional group isomerismCurly arrows, homolytic and heterolytic fissionNucleophiles, electrophiles, radicals and the mechanism steps
Core Organic Chemistry
Topic overviewAlkanes: bonding, shape and boiling pointsCombustion of alkanes and their reaction with halogensThe radical substitution mechanism and its limitationsAlcohols: polarity, solubility and classificationOxidation, dehydration and substitution reactions of alcoholsHydrolysis of haloalkanes and comparing the ratesNucleophilic substitution and carbon-halogen bond strengthCFCs, radicals and the catalytic destruction of ozoneCombining analytical techniques to identify a compound
Alkenes
Topic overviewAlkenes: the double bond, sigma and pi bonding, and shapeE/Z and cis-trans isomerism in alkenesHydrogenation, halogenation and hydration of alkenesElectrophilic addition, carbocation stability and Markownikoff's ruleAddition polymerisation and repeat unitsWaste polymers, and biodegradable and photodegradable alternatives
Organic Synthesis
How Fast?
Topic overviewRate equations, order and the rate constantDeducing orders and finding the units of kWhat the rate equation reveals about the mechanismConcentration-time graphs and continuous monitoringHalf-life and the rate constant of a first-order reactionRate-concentration graphs and the initial rates methodClock reactions, colorimetry and analysing kinetic graphsThe rate-determining step and testing a proposed mechanismTemperature, the rate constant and the Arrhenius equationThe ln k against 1/T graph and finding the activation energy
Physical Chemistry and Transition Elements
Topic overviewMole fraction, partial pressure and ICE tablesKc and Kp expressions, their units and calculationsWhat changes the equilibrium constant, and the reaction quotientLattice enthalpy and the Born-Haber cycleEnthalpy of solution and hydration, and the effect of ionic charge and sizeEntropy and calculating entropy changeGibbs free energy and thermodynamic feasibility
Acids, Bases and Buffers
Topic overviewBrønsted-Lowry acids and bases and their reactionsKa, pKa, pH and the ionic product of waterCalculating the pH of strong acids, strong bases and weak acidspH and hydrogen ion concentrationWhat a buffer is and how it resists a change in pHBuffer calculations and the buffer that controls blood pHTitration curves, choosing an indicator and using a pH meterpH titration curves for the four acid-base combinationsHow an indicator works and choosing the right one
Redox and Electrode Potentials
Topic overviewOxidising and reducing agents, and balancing half-equationsCombining half-equations and using oxidation numbersRedox titrations and their calculationsStandard electrode potentials and setting up half-cellsThe electrochemical series and predicting feasibilityStorage cells and fuel cells
Transition Elements
Topic overviewLigands, complex ions and coordination numberElectron configurations from Sc to Zn, and which are transition elementsVariable oxidation states, coloured ions and catalysisThe shapes of complexes, stereoisomerism and cisplatinLigand substitution, haemoglobin and the copper complexesHydroxide precipitates of iron, manganese and chromiumRedox interconversions of iron, chromium and copperWhy ligand substitution happens and the changes it causesPrecipitation reactions written as aqua complexesDissolving hydroxides in excess ammonia and distinguishing the ions
Aromatic Compounds
Topic overviewThe delocalised model of benzene and the evidence for itNitration, halogenation and Friedel-Crafts reactions of benzeneThe reactions of phenol, and directing effectsElectrophilic substitution and directing effectsPhenol: acidity, bromination and nitrationWhy phenol is more reactive than benzene, and planning a synthesis
Organic Chemistry and Analysis
Topic overviewOxidation and reduction of carbonyls, and the addition of HCNThe nucleophilic addition mechanism2,4-DNPH and Tollens' reagentCarboxylic acids: solubility and reactions with metals, carbonates and basesEsterification and the hydrolysis of estersAcyl chlorides and their reactions with alcohols, amines and ammoniaAmines as bases, and preparing aliphatic aminesSecondary and tertiary amines, and preparing aromatic aminesAmino acids, their reactions, and amidesOptical isomerism and identifying a chiral centreCondensation polymerisation and the ester and amide linkagesHydrolysing condensation polymers and telling them from addition polymersNitriles from haloalkanes and from carbonyl compoundsFriedel-Crafts reactions and lengthening the carbon chainThin-layer and gas chromatography, Rf values and retention timesTest-tube tests for the organic functional groupsTests for the inorganic ions and interpreting chromatograms
Spectroscopy
Topic overviewCarbon-13 and proton NMR: peaks, chemical shift and integrationSpin-spin splitting and predicting a spectrumTMS, deuterated solvents and the D₂O shakeCombining elemental analysis, mass spectrometry, IR and NMRMolecular formula from the molecular ion, and fragmentation lossesWhat IR and NMR each contribute to a structureInfrared absorption, global warming and breathalysersA systematic approach and the degree of unsaturation
Periodic Table and Energy
- 15 subtopics
- 28 things to know
- Components 01 and 03
What Periodic Table and Energy covers
Periodicity and the trends that follow from electron configuration, the reactions of Group 2 and the halogens, the qualitative tests for the common ions, and the collision-theory account of reaction rate including catalysts and the Boltzmann distribution.
Where it is assessed
Components 01 and 03
Periodic Table, Elements and Physical Chemistry, then the unified paper.
Check the OCR specification ↗The 15 subtopics
Each one has its own page.
- Periodicity and the electron configurations of periods 2 and 3Recall questions on what fixes the order of the elements, why a group shares properties, and the electron configurations of lithium through argon.Open →
- The blocks, and first and successive ionisation energiesRecall questions on the s, p and d blocks, the definition of first ionisation energy, the trends across a period and down a group, and the dips at boron and at oxygen.Open →
- Metallic and giant covalent structures and their propertiesRecall questions on metallic bonding, the structures of diamond, graphite, graphene and silicon, and why each conducts, melts and dissolves as it does.Open →
- Group 2 reactions with oxygen, water and acidsRecall questions on the outer configuration, the 2+ ion formed, and the products and the trend in vigour when Group 2 metals meet oxygen, water and dilute acid.Open →
- Ionisation energy down Group 2 and the alkalinity of the hydroxidesRecall questions on atomic radius, shielding and nuclear attraction down the group, and why the hydroxide solutions become more alkaline.Open →
- Uses of Group 2 compounds in agriculture and medicineRecall questions on calcium hydroxide on acid soil, magnesium hydroxide and calcium carbonate as antacids, and why these compounds count as bases.Open →
- The halogens: boiling points, London forces and reactivityRecall questions on the diatomic molecules, why boiling point rises down the group through polarisability and London forces, and the outer configuration they share.Open →
- Halogen displacement reactions and the colours seenRecall questions on which halogen displaces which, the ionic equations, and the colours in aqueous solution and in an organic solvent.Open →
- Disproportionation and the chlorination of waterRecall questions on the definition of disproportionation, chlorine with water and with cold dilute sodium hydroxide, and the benefits and risks of chlorinating water.Open →
- Testing for halide ions with silver nitrate and ammoniaRecall questions on the silver nitrate test, the three precipitate colours, and how their solubility in dilute and concentrated ammonia separates them.Open →
- Testing for carbonate, sulfate and halide ionsRecall questions on the acid test for carbonate, the barium chloride test for sulfate, and why nitric acid is added before the halide test.Open →
- Testing for ammonium ions and the order of the testsRecall questions on the hydroxide test for ammonium, and why carbonate must be tested before sulfate and sulfate before halide.Open →
- Concentration, pressure and measuring reaction rateRecall questions on why concentration and pressure raise the rate through collision frequency, and on measuring rate from the gradient of a graph.Open →
- Catalysts and their industrial importanceRecall questions on the definition of a catalyst, the lowered activation energy, homogeneous against heterogeneous, and the economic and sustainability arguments.Open →
- The Boltzmann distribution, temperature and catalystsRecall questions on the shape of the distribution, what the area under it represents, and how raising the temperature or adding a catalyst changes the proportion of molecules able to react.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What defines a p-block and a d-block element, and what are successive ionisation energies?
Process
Why does first ionisation energy rise across a period, and why are those of boron and oxygen lower than expected?
Process
Why do ionisation energies dip between magnesium and aluminium and between phosphorus and sulfur, and what is metallic bonding?
Key term
What is the structure of silicon, and why do metals and giant covalent substances have high melting points?
Process
What happens to the two outer s electrons when a Group 2 metal reacts, and what ion is formed?
Numbers
What oxide does a Group 2 metal form with oxygen, what forms when it reacts with a dilute acid, and how does the vigour of reaction change down the group?
Process
How do the first and second ionisation energies, the atomic radius and the shielding change down Group 2?
Numbers
Write the equation representing the second ionisation of a Group 2 element.
Key term
What product is formed when a Group 2 oxide reacts with water?
Numbers
How does polarisability change down Group 7, what does greater polarisability do to the dipoles, and why do stronger London forces give higher boiling points?
Numbers
What are the ionic equations for chlorine and bromine displacing iodide, and what colours do the halogens show in water?
Numbers
What is disproportionation, and what happens when chlorine reacts with water?
Numbers
What is the equation for chlorine reacting with cold dilute sodium hydroxide, how do chlorine's oxidation states change, and what is the ionic equation?
Key term
What is seen when dilute acid is added to a carbonate, how is the gas tested, and what observation confirms carbon dioxide?
Numbers
Which reagent tests for sulfate ions, what is observed, and what is the ionic equation for the reaction?
Key term
Why is dilute nitric acid added before the halide test, which reagent is then added, and what does a chloride give?
Process
What property of silver sulfate explains why testing for sulfate must precede testing for halide?
Numbers
Why does raising the concentration or the pressure of the reactants increase the rate of reaction?
Numbers
What does the gradient of a concentration-time graph give, and what does Δt represent in the rate equation?
Numbers
What is a catalyst, how does it increase the rate, and how does the activation energy peak of a catalysed reaction compare on an enthalpy profile?
Key term
What are homogeneous and heterogeneous catalysts, and why are catalysts economically important?
Key term
Describe one technique for investigating reaction rates that involves a balance.
Process
How does lowering the activation energy affect the area under the Boltzmann curve beyond the activation energy?
Key term
What is the structure of a metal, why do metals conduct electricity, and why do diamond and silicon not?
Process
Why does the alkalinity of Group 2 hydroxide solutions increase down the group?
Process
What type of reaction occurs when calcium hydroxide is added to acidic soil?
Numbers
Which reagent tests for halide ions, what is the ionic equation with bromide, and how does silver bromide behave in ammonia?
Take Periodic Table and Energy further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Halogen vs Halide ion
Halogen: a Group 17 element in its uncombined form. Halide ion: a negative species formed when a Group 17 atom gains an electron.
Disproportionation vs Displacement
Disproportionation: one element undergoing oxidation and reduction in the same reaction. Displacement: a more reactive element replacing a less reactive element.
Homogeneous catalyst vs Heterogeneous catalyst
Homogeneous catalyst: a catalyst in the same phase as the reactants. Heterogeneous catalyst: a catalyst in a different phase from the reactants.
Questions from this topic
Each one with the model answer underneath.
- 1
What property of elements determines their order in the periodic table?
Model answer
Elements are arranged by increasing atomic (proton) number.
- 2
What term describes the repeating trends in physical and chemical properties observed across periods?
Model answer
Periodicity.
- 3
Why do elements in the same group have similar chemical properties?
Model answer
Elements in the same group have similar electron configurations in their outer shell, giving them similar chemical properties.
- 4
State the electron configuration of lithium.
Model answer
1s² 2s¹
- 5
State the electron configuration of beryllium.
Model answer
1s² 2s²
- 6
State the electron configuration of boron.
Model answer
1s² 2s² 2p¹
What is inside Levo
Six ways to work the same material.
Periodic Table and Energy revision questions
- What does Periodic Table and Energy cover in OCR A-Level Chemistry?
- 15 subtopics: periodicity and the electron configurations of periods 2 and 3, the blocks, and first and successive ionisation energies, metallic and giant covalent structures and their properties, group 2 reactions with oxygen, water and acids, ionisation energy down group 2 and the alkalinity of the hydroxides, uses of group 2 compounds in agriculture and medicine, the halogens: boiling points, london forces and reactivity, halogen displacement reactions and the colours seen, disproportionation and the chlorination of water, testing for halide ions with silver nitrate and ammonia, testing for carbonate, sulfate and halide ions, testing for ammonium ions and the order of the tests, concentration, pressure and measuring reaction rate, catalysts and their industrial importance and the boltzmann distribution, temperature and catalysts. Each one has its own page with questions and model answers.
- How is Periodic Table and Energy organised?
- By the OCR H432 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Periodic Table and Energy, on a schedule.
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