AQA A-Level Chemistry | Complete Revision Companion
Questions That Repeat
Frequently
And How to Answer Them
30 Topics | Mark-Scheme Answers | Exam Tips Included
Step-by-step worked solutions | Common mistakes exposed
Covers AS and A2 | Written for AQA Specification
Mechanisms • Calculations • Definitions • Spectroscopy
30 55+ AS + A2 100%
Topics Questions Coverage AQA Spec
Your Complete Revision Companion for AQA A-Level Chemistry
Boost Your Grade | Master Every Question Type
,AQA Chemistry A-Level | Questions That Repeat Frequently and How to Answer Them Page 2
Table of Contents
Your roadmap to exam success
1 Atomic Structure & Mass Spectrometry Ions, isotopes, TOF, ionisation energy ▶
2 Bonding – Ionic, Covalent & Metallic Lattice, coordinate bonds, intermolecular forces ▶
3 Shapes of Molecules & Bond Angles VSEPR theory, lone pairs, bond angles ▶
4 Energetics – Enthalpy Changes Hess's law, bond enthalpies, calorimetry ▶
5 Kinetics – Rates of Reaction Maxwell-Boltzmann, rate equations, catalysts ▶
6 Equilibria & Le Chatelier's Principle Kc, Kp, Haber process ▶
7 Oxidation States & Redox Half-equations, electrochemical cells ▶
8 Periodicity – Period 3 Elements Oxides, chlorides, properties ▶
9 Group 2 – Alkaline Earth Metals Trends, reactions, uses ▶
1
Group 7 – The Halogens Oxidising power, halide tests ▶
0
1
Introduction to Organic Chemistry Isomers, homologous series, naming ▶
1
1
Alkanes & Halogenoalkanes Free radical substitution, SN1 vs SN2 ▶
2
1
Alkenes & Addition Reactions Electrophilic addition, Markovnikov's rule ▶
3
1
Alcohols & Oxidation Oxidation products, esterification ▶
4
1
Organic Analysis – IR & Mass Spectra Functional groups, fragments ▶
5
1
Thermodynamics – Lattice Enthalpy Born-Haber cycles, entropy, Gibbs ▶
6
1
Electrode Potentials & Cells EMF, feasibility, standard conditions ▶
7
1
Acids, Bases & Buffers Ka, pH calculations, buffer action ▶
8
1
Further Equilibria – Kc and Kp Expressions, units, temperature effects ▶
9
2
Transition Metals & Complex Ions Colour, d–d transitions, configurations ▶
0
2
Reactions of Transition Metal Ions Precipitation, ligand substitution ▶
1
2
Carbonyl Compounds Nucleophilic addition, aldehyde vs ketone tests ▶
2
2
Carboxylic Acids & Derivatives Acyl chlorides, esters, amides ▶
3
2
Aromatic Chemistry Benzene, nitration, electrophilic substitution ▶
4
2
Amines & Amino Acids Basicity, zwitterions, peptide bonds ▶
5
2
Polymers Addition vs condensation, biodegradability ▶
6
2
DNA & Medicines Chirality, drug action, receptors ▶
7
Boost Your Grade | Master Every Question Type | AQA Specification
,AQA Chemistry A-Level | Questions That Repeat Frequently and How to Answer Them Page 3
2
NMR Spectroscopy Chemical shift, splitting, integration ▶
8
2
Chromatography TLC, GC, Rf values ▶
9
3
Exam Strategy & Final Tips Command words, timing, common errors ▶
0
Boost Your Grade | Master Every Question Type | AQA Specification
, AQA Chemistry A-Level | Questions That Repeat Frequently and How to Answer Them Page 4
1. Atomic Structure & Mass Spectrometry
Questions on atomic structure appear in virtually every AQA paper. Examiners test isotopes,
ionisation energies, electron configurations, and how a mass spectrometer works. Learn the patterns
below and you will pick up marks quickly.
Q: What is an isotope? Give one example.
Answer:
✔ Isotopes are atoms of the same element with the same number of protons but different numbers
of neutrons.
✔ Example: Carbon-12 (¹²C) and Carbon-14 (¹⁴C) — identical chemical properties because same
electron arrangement.
EXAM TIP: Always state 'same protons, different neutrons' — not just 'same element, different mass'.
One mark is reserved for the neutron point.
Stage What Happens Key Detail
1 – Ionisation Sample vaporised; electrospray or electron Electrospray → 1+ ions;
bombardment removes electrons e-bombardment → 1+ or fragments
2– Ions accelerated by electric field to same Lighter ions move faster
Acceleration kinetic energy
3 – Drift region Ions travel across field-free region Lighter ions reach detector sooner
4 – Detection Ions hit detector; time of flight recorded m/z calculated from flight time
Q: Define first ionisation energy and explain the trend across Period 3.
Answer:
✔ First ionisation energy: energy to remove one mole of electrons from one mole of gaseous atoms
→ one mole of gaseous 1+ ions.
✔ Equation: X(g) → X⁺(g) + e⁻
✔ General increase across Period 3 due to increasing nuclear charge attracting electrons more
strongly.
✔ Dip at Al (vs Mg): Al loses a 3p electron, higher in energy and shielded by the 3s sub-level.
✔ Dip at S (vs P): S has a paired 3p electron; electron–electron repulsion makes removal easier.
EXAM TIP: The two dips (Mg→Al and P→S) are classic 2-mark questions. Memorise both explanations
word-for-word.
Boost Your Grade | Master Every Question Type | AQA Specification
Questions That Repeat
Frequently
And How to Answer Them
30 Topics | Mark-Scheme Answers | Exam Tips Included
Step-by-step worked solutions | Common mistakes exposed
Covers AS and A2 | Written for AQA Specification
Mechanisms • Calculations • Definitions • Spectroscopy
30 55+ AS + A2 100%
Topics Questions Coverage AQA Spec
Your Complete Revision Companion for AQA A-Level Chemistry
Boost Your Grade | Master Every Question Type
,AQA Chemistry A-Level | Questions That Repeat Frequently and How to Answer Them Page 2
Table of Contents
Your roadmap to exam success
1 Atomic Structure & Mass Spectrometry Ions, isotopes, TOF, ionisation energy ▶
2 Bonding – Ionic, Covalent & Metallic Lattice, coordinate bonds, intermolecular forces ▶
3 Shapes of Molecules & Bond Angles VSEPR theory, lone pairs, bond angles ▶
4 Energetics – Enthalpy Changes Hess's law, bond enthalpies, calorimetry ▶
5 Kinetics – Rates of Reaction Maxwell-Boltzmann, rate equations, catalysts ▶
6 Equilibria & Le Chatelier's Principle Kc, Kp, Haber process ▶
7 Oxidation States & Redox Half-equations, electrochemical cells ▶
8 Periodicity – Period 3 Elements Oxides, chlorides, properties ▶
9 Group 2 – Alkaline Earth Metals Trends, reactions, uses ▶
1
Group 7 – The Halogens Oxidising power, halide tests ▶
0
1
Introduction to Organic Chemistry Isomers, homologous series, naming ▶
1
1
Alkanes & Halogenoalkanes Free radical substitution, SN1 vs SN2 ▶
2
1
Alkenes & Addition Reactions Electrophilic addition, Markovnikov's rule ▶
3
1
Alcohols & Oxidation Oxidation products, esterification ▶
4
1
Organic Analysis – IR & Mass Spectra Functional groups, fragments ▶
5
1
Thermodynamics – Lattice Enthalpy Born-Haber cycles, entropy, Gibbs ▶
6
1
Electrode Potentials & Cells EMF, feasibility, standard conditions ▶
7
1
Acids, Bases & Buffers Ka, pH calculations, buffer action ▶
8
1
Further Equilibria – Kc and Kp Expressions, units, temperature effects ▶
9
2
Transition Metals & Complex Ions Colour, d–d transitions, configurations ▶
0
2
Reactions of Transition Metal Ions Precipitation, ligand substitution ▶
1
2
Carbonyl Compounds Nucleophilic addition, aldehyde vs ketone tests ▶
2
2
Carboxylic Acids & Derivatives Acyl chlorides, esters, amides ▶
3
2
Aromatic Chemistry Benzene, nitration, electrophilic substitution ▶
4
2
Amines & Amino Acids Basicity, zwitterions, peptide bonds ▶
5
2
Polymers Addition vs condensation, biodegradability ▶
6
2
DNA & Medicines Chirality, drug action, receptors ▶
7
Boost Your Grade | Master Every Question Type | AQA Specification
,AQA Chemistry A-Level | Questions That Repeat Frequently and How to Answer Them Page 3
2
NMR Spectroscopy Chemical shift, splitting, integration ▶
8
2
Chromatography TLC, GC, Rf values ▶
9
3
Exam Strategy & Final Tips Command words, timing, common errors ▶
0
Boost Your Grade | Master Every Question Type | AQA Specification
, AQA Chemistry A-Level | Questions That Repeat Frequently and How to Answer Them Page 4
1. Atomic Structure & Mass Spectrometry
Questions on atomic structure appear in virtually every AQA paper. Examiners test isotopes,
ionisation energies, electron configurations, and how a mass spectrometer works. Learn the patterns
below and you will pick up marks quickly.
Q: What is an isotope? Give one example.
Answer:
✔ Isotopes are atoms of the same element with the same number of protons but different numbers
of neutrons.
✔ Example: Carbon-12 (¹²C) and Carbon-14 (¹⁴C) — identical chemical properties because same
electron arrangement.
EXAM TIP: Always state 'same protons, different neutrons' — not just 'same element, different mass'.
One mark is reserved for the neutron point.
Stage What Happens Key Detail
1 – Ionisation Sample vaporised; electrospray or electron Electrospray → 1+ ions;
bombardment removes electrons e-bombardment → 1+ or fragments
2– Ions accelerated by electric field to same Lighter ions move faster
Acceleration kinetic energy
3 – Drift region Ions travel across field-free region Lighter ions reach detector sooner
4 – Detection Ions hit detector; time of flight recorded m/z calculated from flight time
Q: Define first ionisation energy and explain the trend across Period 3.
Answer:
✔ First ionisation energy: energy to remove one mole of electrons from one mole of gaseous atoms
→ one mole of gaseous 1+ ions.
✔ Equation: X(g) → X⁺(g) + e⁻
✔ General increase across Period 3 due to increasing nuclear charge attracting electrons more
strongly.
✔ Dip at Al (vs Mg): Al loses a 3p electron, higher in energy and shielded by the 3s sub-level.
✔ Dip at S (vs P): S has a paired 3p electron; electron–electron repulsion makes removal easier.
EXAM TIP: The two dips (Mg→Al and P→S) are classic 2-mark questions. Memorise both explanations
word-for-word.
Boost Your Grade | Master Every Question Type | AQA Specification
