Ions
Ion-focused reasoning across atomic structure, electrolysis, qualitative analysis, and acid-base chemistry.
This route helps when you keep missing the same type of question across different topics. Use it to combine lesson notes with linked practice and tools in one place.
Notes and Hubs in This Route
- Introduction to Acids
Acids: aqueous hydrogen ions, complete versus partial ionisation, and the distinction between acid strength and concentration.
- Acids, Bases & Salts
Acids, bases and salts hub: aqueous ions, pH, core reactions, solubility rules, salt preparation, ammonia and exam practice.
- Why alloys have different properties
Identify alloys from composition and particle diagrams, explain how different-sized particles hinder layer movement, and distinguish hardness from other material properties.
- Electroplating: Growing a Metal Coating
Explain how a metal coating grows on the cathode, choose the electrolyte and anode, and connect electron transfer to electrode changes.
- Atomic structure and particle counts
Describe the nucleus and electron shells, compare subatomic particles, and count protons, neutrons and electrons in atoms and single-atom ions.
- Simple Electric Cells
Learn how simple cells produce electrical energy: use the reactivity series to identify polarity, electron flow, observations and half-equations.
- Electrolysis of Aqueous Compounds
Aqueous electrolysis: water vs solute ions, preferential discharge rules, and how concentration and electrode type change the products.
- Electrolysis of Molten Compounds
Molten electrolysis: predict cathode/anode products from ions present (no water competing), then write correct half-equations and overall equations.
- Electron configuration
Arrange electrons in shells for the first 20 elements, identify valence electrons and use neutral-atom arrangements to find group and period.
- Writing chemical symbols and formulae
Read chemical notation, balance ion charges and use brackets correctly. Distinguish simplest atom ratios from the actual atoms in a molecule.
- Writing ionic equations
Ionic equations: split aqueous ions, cancel spectator ions, and balance atoms and charge for common precipitation, neutralisation, and gas reactions.
- Introduction to Bases
Bases and alkalis: definitions, aqueous hydroxide ions, neutralisation and the ammonium-ion reaction.
- Ionic bonding: forming ions and balancing charges
Form ions by electron loss and gain, show sodium chloride and magnesium chloride with dot-and-cross diagrams, and balance charges to write formulas.
- Ionic structures and properties
Use the giant lattice and ion mobility to explain high melting temperatures and the electrical conductivity of solid, molten and dissolved ionic compounds.
- Metal Extraction and Compound Stability
Explain metal-oxide reduction, the effects of heating carbonates and how reactivity affects metal extraction.
- Metallic bonding and metal properties
Use positive metal ions and delocalised electrons to explain electrical and thermal conduction, melting behaviour, malleability and ductility.
- Metals and Non-Metals
Compare metals and non-metals, link outer electrons to ion formation, and apply the metallic-to-non-metallic trend across a period.
- Oxides
Oxides: classify acidic/basic/amphoteric/neutral, and write the key reactions and equations examiners expect.
- pH Scale & Indicators
pH scale & indicators: acidic/neutral/alkaline ranges, key colour changes (litmus/universal indicator), and how to answer exam-style questions.
- Physical & Chemical Properties of Acids
Acid properties and reactions: indicator behaviour, and the 3 core reactions with metals, bases and carbonates—plus key observations and gas tests.
- Physical & Chemical Properties of Alkalis
Alkali properties and reactions: pH > 7 and red litmus → blue, neutralisation, ammonium salts test (ammonia), and precipitate formation.
- Preparing Insoluble Salts
Prepare an insoluble salt by precipitation: choose soluble ion sources, collect the residue, wash away dissolved impurities and dry the product.
- Ammonia and Ammonium Salts
Ammonia and ammonium ions: the damp-red-litmus gas test, the ammonium-ion test and the balanced ionic equations.
- Purifying Copper by Electrolysis
Explain how copper transfers from an impure anode to a pure cathode, track copper ions and electrode masses, and distinguish impurity paths.
- Qualitative Analysis (QA)
Qualitative analysis hub: observation-to-inference method, ion and gas tests, key reagents and exam wording. Practise the topic with its check.
- Qualitative Analysis: Tests for Anions
Tests for carbonate, chloride, iodide, nitrate and sulfate ions, including reagent order, observations, interference and ionic equations.
- Qualitative Analysis: Tests for Cations
Cation tests for aluminium, ammonium, calcium, copper(II), iron(II), iron(III) and zinc using aqueous NaOH and ammonia.
- The Reactivity Series of Metals
Use water, steam, dilute-acid and displacement observations to compare metals and explain electron transfer.
- Rusting and Protecting Iron
Use controlled rusting evidence to explain barriers, galvanising and sacrificial protection with magnesium.
- Salts
Salts: definitions, formulae, solubility rules, precipitate prediction and selecting excess-solid, titration or precipitation methods.
- Reading the Periodic Table
Learn how proton number and electron configuration determine Periodic Table position, common ion charges, group similarities and metallic character.
- Types of Electrodes in Electrolysis
Inert vs reactive electrodes: explain how a copper anode can dissolve instead of producing oxygen and how this affects products, mass and concentration.
- What Is Electrolysis?
Understand why electrolytes need mobile ions, distinguish charge movement in wires and liquids, and identify oxidation and reduction at the electrodes.
- What is matter?
Matter: made of atoms, molecules or ions, and the particle-model properties of solids, liquids and gases (shape, volume, compressibility).
- Writing and Checking Electrode Half-Equations
Construct electrode half-equations, balance atoms and charge, cancel equal electron transfers, and connect the equations to observed products.
- Redox Chemistry
K324 and 6092 Topic 7 Redox Chemistry hub: oxidation and reduction, oxidation states, redox tests, electrolysis, electroplating, simple cells and fuel cells.
- Acids and Bases (Theories) (A Level)
A Level acid–base theories notes: apply Arrhenius, Brønsted–Lowry and Lewis models, identify conjugate pairs, and explain Lewis adduct formation.
- Arrhenius, Brønsted–Lowry, Lewis Definitions (A Level)
Choose the right acid–base definition (Arrhenius, Brønsted–Lowry, Lewis) and write one-line justifications that match exam wording.
- Atomic Orbitals: Energies and Shapes (A Level)
Describe the number, relative energies, and shapes of s, p and d orbitals (n=1–3) plus 4s and 4p, and use them to support electron configuration answers.
- Atomic Structure (A Level)
A Level atomic structure notes: nuclides and ions, orbitals and electron configurations, and first/successive ionisation energies (trends, anomalies, data).
- Bond Energy, Bond Length and Bond Polarity (A Level)
Define bond energy and bond length, and compare covalent bond reactivity using bond energy, bond length, and bond polarity.
- Chemical Bonding (A Level)
A Level chemical bonding notes: ionic/covalent/dative bonding, VSEPR shapes, sigma and pi bonds, intermolecular forces, and structure–property links.
- Conjugate Pairs and Amphoteric Species (A Level)
Identify conjugate acid–base pairs, distinguish amphiprotic from broader amphoteric behaviour, and track one-proton charge changes.
- Dative Bonding and Common Examples (A Level)
Describe coordinate (dative covalent) bonding in ammonium ions and aluminium chloride dimers with the correct electron-pair origin.
- First Ionisation Energy Trends (A Level)
Define first ionisation energy and explain periodic trends using nuclear charge, shielding, and distance from the nucleus.
- Group 17 Chemistry Trends (A Level)
Explain Group 17 trends from chlorine to iodine: volatility, oxidising strength from E° values, displacement reactions, and hydrogen-halide thermal stability.
- Group 2 Chemistry Trends (A Level)
Explain Group 2 trends from Mg to Ba: electronic structure, atomic properties, reducing strength from E° values, and carbonate thermal stability.
- Group 1 Elements: The Alkali Metals
Learn Group 1 alkali-metal properties, melting-point and reactivity trends, water-reaction observations, balanced equations and exam explanations.
- Group 17 Elements: The Halogens
Learn Group 17 halogen colours and states, the reactivity trend, displacement predictions, balanced ionic equations and precise observations.
- Intermolecular Forces and Properties (A Level)
Compare London forces, permanent dipole–dipole, and hydrogen bonding, and explain how IMF strength affects boiling point, solubility, and viscosity.
- Ionic and Covalent Bonding Models (A Level)
Describe ionic, covalent and metallic bonding as electrostatic attractions, and draw the syllabus dot-and-cross examples.
- Lewis Adducts and Exam Phrasing (A Level)
Recognise Lewis acid–base reactions as adduct formation, and match common exam phrases (‘electron-pair acceptor/donor’) to correct species.
- Molecular Shapes and Bond Angles (VSEPR) (A Level)
Use VSEPR to predict 3D shapes and bond angles, including lone pair effects and common molecules like NH3, H2O, CO2, and SF6.
- Noble Gases (Group 18)
Learn why Group 18 noble gases are monatomic and very unreactive, and link helium, neon and argon to their syllabus uses.
- Orbitals and Electron Configuration (A Level)
Use orbitals (s/p/d) to write electron configurations for atoms and ions, including the 4s-before-3d removal rule for transition-metal cations.
- Period 3 Elements: Melting Point and Conductivity (A Level)
Explain melting point and electrical conductivity trends across Period 3 (Na→Cl) using structure and bonding: metallic, giant covalent and simple molecular.
- Period 3 Oxides and Chlorides (A Level)
Explain Period 3 oxidation numbers, oxide and chloride bonding, reactions with water, and acid-base behaviour of the specified oxides and hydroxides.
- The Periodic Table (A Level)
A Level periodicity notes: physical trends, Period 3 oxides, hydroxides and chlorides, Group 2 and 17 redox trends, and data-based deductions.
- Periodic Trends (Radius, IE, EN) (A Level)
Explain trends in atomic radius, ionic radius, ionisation energy, and electronegativity using nuclear charge, shielding, and electron shells.
- Sigma and Pi Bonds (Orbital Overlap) (A Level)
Describe covalent bonding through head-on and sideways overlap of s and p orbitals, giving sigma and pi bonds.
- Solids: Structure and Physical Properties (A Level)
Describe the five specified solid lattices, link bonding to physical properties, and deduce structure from property data.
- Subatomic Particles, Isotopes, Ions (A Level)
Use proton/neutron/electron facts to interpret nuclide symbols, explain isotopes and ions, and predict deflection of beams in electric fields.
- Successive Ionisation Energies (A Level)
Interpret successive ionisation energy data to deduce valence electrons and group, and explain large jumps using shell changes.
- The Periodic Table
Periodic Table hub covering groups, periods, Group 1 and 17 trends, noble gases, transition elements and the reactivity series.
- Transition Elements
Learn the typical K324 / 6092 properties of transition elements: high melting points and densities, variable oxidation states, coloured compounds and catalysts.
- The Particulate Nature of Matter
Chemistry Matter hub: particle model, atoms/electron configuration, and bonding (ionic, covalent, metallic, giant covalent). Practise the topic with its check.
- Common Ion Effect and Complex Ions (A Level)
Predict solubility changes using the common ion effect, and explain how complex-ion formation increases solubility in linked equilibria.
- Complex Ions, Ligands, Ligand Exchange (A Level)
Define ligands and complexes, then explain the prescribed copper(II) water, ammonia and chloride exchanges and oxygen/carbon monoxide exchange in haemoglobin.
- d-Orbital Splitting and Colour (A Level)
Use octahedral d-orbital orientation, splitting and d–d transitions to explain why many transition-metal complexes are coloured.
- Electrochemistry (A Level)
A Level electrochemistry notes: standard electrode potentials, cell EMF and spontaneity, redox equations from half-equations, and electrolysis/Faraday’s law.
- Ksp and Solubility Calculations (A Level)
Write Ksp expressions, calculate molar solubility, and predict precipitation using Qsp vs Ksp, with a repeatable exam workflow.
- Lattice Energy and Born–Haber Cycles (A Level)
Define lattice energy, predict trends with ionic charge/radius, and use Born–Haber cycles to connect lattice energy to formation enthalpy.
- Qualitative Analysis: Anions and Gases (A Level)
Paper 4-ready anion and gas tests: carbonates, sulfates, halides, nitrates, ammonia, carbon dioxide, chlorine, and sulfur dioxide.
- Qualitative Analysis: Cations (Table) (A Level)
A Paper 4-ready cations table: tests with NaOH/NH3, key precipitate colours, solubility in excess, and confirmatory notes.
- Qualitative Analysis Notes (A Level)
One-page Paper 4 qualitative analysis notes: how to write observations, key ions and gases, and the phrasing examiners expect.
- Transition Elements (A Level)
A Level transition elements notes: electron configurations, complex ions, variable oxidation states/redox, colour (d splitting), and catalysis.
- Transition Elements: Definition and Electron Configurations (A Level)
Apply both branches of the 9476 transition-element definition, write first-row atom and ion configurations, and explain the series’ physical trends.
- Transition-metal Catalysis (A Level)
Explain transition-element catalysis through surface adsorption or regenerated redox intermediates across the prescribed heterogeneous and homogeneous contexts.
- Variable Oxidation States and Redox Systems (A Level)
Explain variable oxidation states in transition elements, and write key redox half-equations for Fe, MnO4− and Cr2O7^2− with conditions and colour changes.
- Writing Redox Equations from Half-equations (A Level)
Combine half-equations into balanced overall redox equations, using E° values to decide which half-equation is reversed (oxidation).