Chemistry
Form 4 · 43 topics available
Chapter 1 · Introduction to Chemistry
Development in the Field of Chemistry
How chemistry grew from ancient alchemy into a modern science, and the many careers and industries it supports today.
OpenScientific Investigation in Chemistry
The steps of a scientific investigation — from making a hypothesis to controlling variables and drawing a valid conclusion.
OpenUsage, Management and Handling of Apparatus and Materials
How to choose the right apparatus, read hazard symbols, and handle chemicals safely in the chemistry laboratory.
OpenChapter 2 · Matter and the Atomic Structure
Basic Concept of Matter
Matter, particles and the kinetic theory: how solids, liquids and gases differ and how they change state.
OpenThe Development of the Atomic Model
From Dalton's solid sphere to the modern model: how experiments changed our picture of the atom.
OpenStructure of the Atom
Protons, neutrons and electrons; proton number, nucleon number and how to work out electron arrangement.
OpenIsotopes and Their Uses
What isotopes are, why they have the same chemical properties, and how they are used in medicine, industry and archaeology.
OpenChapter 3 · The Mole Concept, Chemical Formulae and Equations
Relative Atomic Mass and Relative Molecular Mass
Learn how atomic and molecular masses are measured on the carbon-12 scale and how to calculate Ar and Mr.
OpenThe Mole Concept
Understand the mole as a counting unit, the Avogadro constant, and the key formulae linking mass, moles, particles and gas volume.
OpenChemical Formula
Distinguish empirical from molecular formulae and learn to determine them from masses, percentages and ionic charges.
OpenChemical Equation
Write and balance chemical equations, add state symbols, and use mole ratios for stoichiometric calculations.
OpenChapter 4 · The Periodic Table of Elements
Historical Development of the Periodic Table
Trace how the periodic table developed from Döbereiner and Newlands to Mendeleev and the modern table based on proton number.
OpenArrangement of Elements in the Modern Periodic Table
See how proton number, periods and groups organise the modern table and how electron arrangement explains chemical properties.
OpenElements in Group 18
Explore the noble gases: their full outer shells, chemical inertness, physical trends and everyday uses.
OpenElements in Group 1
Study the alkali metals: their single valence electron, reactions with water, and increasing reactivity down the group.
OpenElements in Group 17
Investigate the halogens: their seven valence electrons, −1 ions, colour and state trends, and decreasing reactivity down the group.
OpenElements in Period 3
Follow the trends across Period 3 — from metallic sodium to non-metallic argon — in atomic size, electronegativity and oxide character.
OpenTransition Elements
Discover the special properties of transition elements: variable oxidation states, coloured compounds, catalysis and complex ions.
OpenChapter 5 · Chemical Bond
Basic Formation of Compounds
Why atoms combine: unstable atoms lose, gain or share electrons to reach a stable noble-gas duplet or octet arrangement.
OpenIonic Bond
An ionic bond is the strong electrostatic force between oppositely charged ions formed when electrons transfer from a metal to a non-metal.
OpenCovalent Bond
A covalent bond forms when two non-metal atoms share one or more pairs of electrons so that each achieves a stable octet or duplet.
OpenHydrogen Bond
A hydrogen bond is a weak intermolecular attraction between an H atom bonded to F, O or N and a lone pair on another electronegative atom.
OpenDative Bond
A dative (coordinate) bond is a covalent bond in which both shared electrons come from just one of the two atoms.
OpenMetallic Bond
A metallic bond is the attraction between a lattice of positive metal ions and a 'sea' of delocalised valence electrons.
OpenIonic and Covalent Compounds
Ionic and covalent compounds differ sharply in melting point, electrical conductivity and solubility because of their different structures.
OpenChapter 6 · Acid, Base and Salt
The Role of Water in Showing Acidic and Alkaline Properties
Water lets acids and alkalis ionise into free H⁺ and OH⁻ ions — without it, they show no acidic or alkaline properties.
OpenpH Value
pH measures how acidic or alkaline a solution is on a 0–14 scale, based on the concentration of hydrogen ions, H⁺.
OpenStrength of Acids and Alkalis
Strength describes the degree of ionisation: strong acids and alkalis ionise fully, weak ones ionise only partially.
OpenChemical Properties of Acids and Alkalis
Acids react with metals, bases and carbonates; alkalis react with acids, ammonium salts and metal ion solutions.
OpenConcentration of Aqueous Solutions
Concentration is the amount of solute in a fixed volume of solution, expressed in g dm⁻³ or mol dm⁻³ (molarity).
OpenStandard Solution
A standard solution has an accurately known concentration, prepared by dissolving a measured mass and making up to the mark in a volumetric flask.
OpenNeutralisation
Neutralisation is the reaction between an acid and a base to form salt and water, summarised by H⁺ + OH⁻ → H₂O.
OpenSalts, Crystals and Their Uses in Daily Life
A salt is an ionic compound formed when the H⁺ of an acid is replaced by a metal or ammonium ion; many form regular crystals.
OpenPreparation of Salts
Soluble salts are made by reacting acid with excess solid then crystallising; insoluble salts are made by precipitation.
OpenEffect of Heat on Salts
Heating salts can drive off water of crystallisation or decompose carbonates and nitrates into gases and solid residues.
OpenQualitative Analysis
Qualitative analysis identifies the cations and anions in a salt using heat, gas tests and reactions with NaOH and NH₃.
OpenChapter 7 · Rate of Reaction
Determination of Rate of Reaction
How chemists measure how fast a reaction goes by tracking a chosen quantity against time.
OpenFactors Affecting the Rate of Reaction
How surface area, concentration, temperature, pressure and catalysts speed up or slow down reactions.
OpenApplication of Rate of Reaction in Daily Life
How we speed up or slow down reactions in cooking, food storage, industry and safety.
OpenCollision Theory
Why reactions need effective collisions with enough energy and the correct orientation to happen.
OpenChapter 8 · Manufactured Substances in Industry
Glass
The main types of glass, what they are made from and how their properties suit different uses.
OpenCeramics
How clay-based ceramics are made, their key properties and where they are used.
OpenComposite Materials
How combining two materials makes a composite that is stronger and better than either one alone.
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