Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Topic 1 · Principles of chemistry
The foundations everything else is built on: particles and states, separating mixtures, atomic structure, the Periodic Table, moles and equations, and the three types of bonding — plus electrolysis.
Every lesson here ends the same way: learn it, teach it to an AI pupil who asks the awkward question, then defend it against the thinker with the strongest claim on it — free · no account needed.
18 lessons, covering 60 specification statements.
What you need to know — the 60 statements, and where each one is taught
Every statement this topic carries, in the specification's own numbering, with Incandio's restatement of what it asks and the lesson that discharges it. Tick them off against your own copy of the specification: this is the topic's revision checklist, not a summary of it. Incandio is aligned to this specification. It is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording — the statement numbers are given so you can check every lesson against your own copy.
| Statement | What it asks | Taught in |
|---|---|---|
| 1.1 | The three states of matter in terms of arrangement, movement and energy of particles | The Three States of Matter |
| 1.2 | Interconversions between the states: their names, how they are achieved, and the particle changes | The Three States of Matter |
| 1.3 | Explaining dilution of coloured solutions and diffusion of gases using particles | The Three States of Matter |
| 1.4 | The terms solvent, solute, solution and saturated solution | Pure Substances, Mixtures and How to Separate Them |
| 1.8 | Classifying a substance as an element, compound or mixture | Pure Substances, Mixtures and How to Separate Them |
| 1.9 | Pure substances have fixed melting and boiling points; mixtures melt or boil over a range | Pure Substances, Mixtures and How to Separate Them |
| 1.10 | Separation techniques: simple distillation, fractional distillation, filtration, crystallisation, paper chromatography | Pure Substances, Mixtures and How to Separate Them |
| 1.11 | How a chromatogram gives information about the composition of a mixture | Pure Substances, Mixtures and How to Separate Them |
| 1.12 | Using Rf values to identify the components of a mixture | Pure Substances, Mixtures and How to Separate Them |
| 1.13 (practical) | Practical: investigate paper chromatography using inks or food colourings | Pure Substances, Mixtures and How to Separate Them |
| 1.14 | The terms atom and molecule | Inside the Atom |
| 1.15 | Atomic structure: positions, relative masses and relative charges of sub-atomic particles | Inside the Atom |
| 1.16 | The terms atomic number, mass number, isotopes and relative atomic mass | Inside the Atom |
| 1.17 | Calculating relative atomic mass from isotopic abundances | Inside the Atom |
| 1.18 | How elements are arranged in the Periodic Table: atomic number, groups and periods | Electronic Configurations and the Periodic Table |
| 1.19 | Deducing the electronic configurations of the first 20 elements from position | Electronic Configurations and the Periodic Table |
| 1.20 | Using electrical conductivity and acid–base character of oxides to classify elements as metals or non-metals | Electronic Configurations and the Periodic Table |
| 1.21 | Identifying an element as a metal or non-metal from its position | Electronic Configurations and the Periodic Table |
| 1.22 | How the electronic configuration of a main group element relates to its position | Electronic Configurations and the Periodic Table |
| 1.23 | Why elements in the same group have similar chemical properties | Electronic Configurations and the Periodic Table |
| 1.24 | Why the noble gases do not readily react | Electronic Configurations and the Periodic Table |
| 1.5 | Solubility in g per 100 g of solvent | Solubility and Solubility Curves |
| 1.6 | Plotting and interpreting solubility curves | Solubility and Solubility Curves |
| 1.7 (practical) | Practical: investigate the solubility of a solid in water at a specific temperature | Solubility and Solubility Curves |
| 1.25 | Writing word and balanced chemical equations, including state symbols | Formulae and Balanced Equations |
| 1.26 | Calculating relative formula masses from relative atomic masses | Formulae and Balanced Equations |
| 1.27 | The mole as the unit for amount of substance | The Mole |
| 1.28 | Calculations involving amount of substance, Ar and Mr | The Mole |
| 1.29 | Calculating reacting masses from experimental data and equations | Reacting Masses and Percentage Yield |
| 1.30 | Calculating percentage yield | Reacting Masses and Percentage Yield |
| 1.31 | Obtaining formulae of simple compounds experimentally, including water of crystallisation | Empirical and Molecular Formulae |
| 1.32 | The terms empirical formula and molecular formula | Empirical and Molecular Formulae |
| 1.33 | Calculating empirical and molecular formulae from experimental data | Empirical and Molecular Formulae |
| 1.36 (practical) | Practical: determine the formula of a metal oxide by combustion or reduction | Empirical and Molecular Formulae |
| 1.34 | Calculations involving amount of substance, volume and concentration in mol/dm³ | Concentration and Gas Volumes |
| 1.35 | Calculations involving gas volumes and the molar volume (24 dm³ at rtp) | Concentration and Gas Volumes |
| 1.37 | How ions are formed by electron loss or gain | Ionic Bonding |
| 1.38 | The charges of the ions named by the specification | Ionic Bonding |
| 1.39 | Writing formulae for compounds formed between those ions | Ionic Bonding |
| 1.40 | Dot-and-cross diagrams showing the formation of ionic compounds by electron transfer | Ionic Bonding |
| 1.41 | Ionic bonding in terms of electrostatic attraction | Ionic Structures and Their Properties |
| 1.42 | Why giant ionic lattices have high melting and boiling points | Ionic Structures and Their Properties |
| 1.43 | Why ionic compounds conduct only when molten or in aqueous solution | Ionic Structures and Their Properties |
| 1.44 | A covalent bond as a shared pair of electrons | Covalent Bonding |
| 1.45 | Covalent bonds in terms of electrostatic attraction | Covalent Bonding |
| 1.46 | Dot-and-cross diagrams for diatomic, inorganic and small organic molecules | Covalent Bonding |
| 1.47 | Why simple molecular substances have low melting and boiling points | Simple Molecular Substances |
| 1.48 | Why melting and boiling points of simple molecular substances rise with relative molecular mass | Simple Molecular Substances |
| 1.51 | Covalent compounds do not usually conduct electricity | Simple Molecular Substances |
| 1.49 | Why giant covalent structures are solids with high melting and boiling points | Giant Covalent Structures |
| 1.50 | How the structures of diamond, graphite and C60 fullerene influence their properties | Giant Covalent Structures |
| 1.52 | Representing a metallic lattice by a 2-D diagram | Metallic Bonding |
| 1.53 | Metallic bonding in terms of electrostatic attraction | Metallic Bonding |
| 1.54 | Explaining typical physical properties of metals, including conductivity and malleability | Metallic Bonding |
| 1.55 | Why covalent compounds do not conduct electricity | Why Substances Conduct — the Four Structures Compared |
| 1.56 | Why ionic compounds conduct only when molten or in solution | Why Substances Conduct — the Four Structures Compared |
| 1.57 | The terms anion and cation | Why Substances Conduct — the Four Structures Compared |
| 1.58 | Electrolysis of molten compounds and aqueous solutions with inert electrodes, and predicting the products | Electrolysis |
| 1.59 | Writing ionic half-equations for the electrode reactions, and classifying them as oxidation or reduction | Electrolysis |
| 1.60 (practical) | Practical: investigate the electrolysis of aqueous solutions | Electrolysis |
The lessons
- The Three States of Matter — What the particles are doing in a solid, a liquid and a gas — and what really changes when ice melts. (1.1, 1.2, 1.3)
- Pure Substances, Mixtures and How to Separate Them — Why a pure substance melts at one temperature, and which separation technique to reach for when. (1.4, 1.8, 1.9, 1.10, 1.11, 1.12, 1.13)
- Inside the Atom — Protons, neutrons and electrons — where they are, what they weigh, what they carry, and how isotopes give an element a decimal mass. (1.14, 1.15, 1.16, 1.17)
- Electronic Configurations and the Periodic Table — Why the table has the shape it has: the group number IS the outer-shell electron count, and everything follows from that. (1.18, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24)
- Solubility and Solubility Curves — Why a solution can be full, why hot water holds more, and how one curve tells you exactly how many crystals you will get back. (1.5, 1.6, 1.7)
- Formulae and Balanced Equations — Why the ash weighs more than the metal, what balancing an equation is really doing, and how to add up a formula mass without losing a bracket. (1.25, 1.26)
- The Mole — Chemists have to count atoms and can only weigh them. The mole is the one idea that turns a mass on a balance into a number of particles. (1.27, 1.28)
- Reacting Masses and Percentage Yield — How much product a reaction should give, how much it actually gives, and why the two are never the same. (1.29, 1.30)
- Empirical and Molecular Formulae — Working out a formula you were never told, from nothing but the masses on a balance. (1.31, 1.32, 1.33, 1.36)
- Concentration and Gas Volumes — Counting particles in a solution you can only measure by volume, and in a gas you cannot weigh at all. (1.34, 1.35)
- Ionic Bonding — Why atoms give electrons away or take them, how far you can predict that from the periodic table, and how to draw it. (1.37, 1.38, 1.39, 1.40)
- Ionic Structures and Their Properties — Why salt melts at 800 °C, why it will not conduct until it does, and why both facts come from the same lattice. (1.41, 1.42, 1.43)
- Covalent Bonding — What two atoms do when neither can afford to give an electron away. (1.44, 1.45, 1.46)
- Simple Molecular Substances — Strong bonds inside, feeble forces outside — and why that makes methane a gas. (1.47, 1.48, 1.51)
- Giant Covalent Structures — The same element, the same bonds — and one form cuts glass while another marks paper. (1.49, 1.50)
- Metallic Bonding — A lattice of positive ions in a sea of electrons that belong to no atom in particular. (1.52, 1.53, 1.54)
- Why Substances Conduct — the Four Structures Compared — One test applied to every structure in the topic, and the two words electrolysis is built on. (1.55, 1.56, 1.57)
- Electrolysis — Using a current to pull a compound apart, and writing down what happens at each electrode. (1.58, 1.59, 1.60)