Chemistry

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This subtopic covers the foundational principles of atomic structure, including the arrangement of protons, neutrons, and electrons, and how these relate to atomic number and mass. Students explore the development of atomic models from Dalton to the quantum model, emphasizing experimental evidence such as scattering experiments. Practical applications include interpreting mass spectra and predicting chemical behavior based on electron configurations.

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Atomic structure

This topic explores the fundamental structure of the atom, focusing on protons, neutrons, and electrons, and the concept of isotopes. It also covers the principles of time-of-flight mass spectrometry and the arrangement of electrons in shells and sub-shells, including the definition and trends of ionisation energies.

Equilibrium constant Kp for homogeneous systems (A-level only)

This topic extends the study of chemical equilibria to homogeneous systems in the gas phase, focusing on the equilibrium constant Kp. Students learn to derive partial pressures from mole fractions and total pressure, construct expressions for Kp, and perform calculations to determine its value. The treatment also covers predicting the qualitative effects of temperature and pressure changes on the position of equilibrium and the value of Kp.

Electrode potentials and electrochemical cells (A-level only)

This topic explores redox reactions occurring in electrochemical cells, where electron transfer between reducing and oxidising agents happens indirectly via an external circuit. It covers the measurement of electrode potentials using the standard hydrogen electrode, the use of the electrochemical series to predict reaction feasibility, and the commercial application of these principles in batteries and fuel cells.

Acids and bases (A-level only)

This topic covers the Brønsted-Lowry theory of acids and bases, focusing on proton transfer in aqueous solutions. It includes the quantitative treatment of pH, the ionic product of water (Kw), the dissociation constant (Ka) for weak acids, and the application of pH curves and buffer solutions.

Amount of substance

This topic covers the fundamental quantitative aspects of chemistry, focusing on the mole as a unit of amount of substance. It includes calculations involving mass, gas volumes, solution concentrations, empirical and molecular formulas, and balanced chemical equations, including atom economy and percentage yield.

Bonding

This topic explores the chemical and physical properties of compounds determined by their bonding and intermolecular forces. It covers ionic, covalent, metallic, and macromolecular structures, alongside molecular shapes, bond polarity, and the nature of intermolecular forces including hydrogen bonding.

Energetics

This topic covers the measurement of enthalpy changes in chemical reactions, which are essential for understanding energy sources like fuels. It includes the study of calorimetry, Hess's Law, and bond enthalpies to quantify energy changes under constant pressure.

Kinetics

This topic explores the factors that influence the rate of chemical reactions, focusing on collision theory and the energy requirements for successful collisions. It covers the Maxwell-Boltzmann distribution to explain how temperature and catalysts affect reaction rates, alongside the qualitative effects of concentration and pressure.

Chemical equilibria, Le Chatelier’s principle and Kc

This topic explores the nature of reversible reactions and the concept of dynamic equilibrium in homogeneous systems. It covers Le Chatelier’s principle to predict the effects of changing conditions on equilibrium position and the mathematical treatment of the equilibrium constant Kc.

Oxidation, reduction and redox equations

This topic covers the fundamental principles of redox reactions, which involve the transfer of electrons from a reducing agent to an oxidising agent. Students learn to assign oxidation states to elements within compounds or ions to identify oxidation and reduction processes and construct balanced overall redox equations from half-equations.

Thermodynamics (A-level only)

This topic explores the thermodynamic principles governing chemical stability and reaction feasibility. It builds upon energetics by linking enthalpy changes with entropy changes to calculate the Gibbs free-energy change, and utilizes Born-Haber cycles to analyze lattice enthalpies.

Rate equations (A-level only)

This topic explores the mathematical relationship between the rate of a chemical reaction and the concentration of its reactants, expressed through rate equations. It also covers the Arrhenius equation to describe the temperature dependence of the rate constant and the use of experimental data to determine reaction orders and mechanisms.

Periodicity

This topic covers the classification of elements into s, p, d, and f blocks based on their position in the Periodic Table and proton number. It also examines the physical trends in atomic radius, first ionisation energy, and melting point for Period 3 elements (Na–Ar), relating these trends to their underlying structure and bonding.

Group 2, the alkaline earth metals

This topic covers the chemical and physical properties of Group 2 elements, known as the alkaline earth metals, from magnesium to barium. It focuses on trends in atomic radius, first ionisation energy, and melting points, as well as the chemical reactions of these elements with water and the solubility trends of their hydroxides and sulfates.

Group 7(17), the halogens

This topic covers the physical and chemical properties of the Group 7 halogens, focusing on trends in electronegativity, boiling points, and reactivity. It explores the oxidising ability of halogens and the reducing ability of halide ions, including specific test-tube reactions for identification and the industrial uses of chlorine.

Properties of Period 3 elements and their oxides (A-level only)

This topic explores the chemical properties of Period 3 elements (Na–S) and their oxides. It focuses on the reactions of these elements with oxygen and water, the resulting pH of the solutions formed, and the trends in melting points and bonding structures across the period.

Transition metals (A-level only)

This topic explores the chemistry of the 3d transition metals (Ti-Cu), focusing on their characteristic properties including complex formation, variable oxidation states, catalytic activity, and the formation of coloured ions. It covers the bonding in complex ions, ligand substitution reactions, the chelate effect, and the use of transition metal chemistry in industrial and biological contexts.

Reactions of ions in aqueous solution (A-level only)

This topic focuses on the reactions of transition metal ions in aqueous solution, specifically the formation of metal-aqua ions. It explores the acidity of these ions and the amphoteric nature of certain metal hydroxides, providing a practical basis for identifying transition metal ions through test-tube reactions.

Introduction to organic chemistry

This topic introduces the study of covalent carbon compounds, covering nomenclature, structural representation, and reaction mechanisms. It establishes the foundational principles for understanding organic chemistry, including isomerism and the use of IUPAC naming conventions for simple chains and rings.

Aromatic chemistry (A-level only)

Aromatic chemistry focuses on the structure and reactivity of benzene as a model aromatic compound. It examines the delocalisation of p-electrons, which confers extra stability compared to theoretical cyclohexa-1,3,5-triene, and explores electrophilic substitution mechanisms including nitration and Friedel-Crafts acylation.

Amines (A-level only)

This topic covers the chemistry of amines, which are derivatives of ammonia where hydrogen atoms are replaced by alkyl or aryl groups. It focuses on their preparation methods, their nature as weak bases, and their role as nucleophiles in substitution and addition-elimination reactions.

Polymers (A-level only)

This topic covers the formation and properties of condensation polymers, including polyesters and polyamides. It also addresses the environmental impact of both addition and condensation polymers, focusing on biodegradability and the challenges associated with their disposal and recycling.

Amino acids, proteins and DNA (A-level only)

This topic explores the structure, bonding, and chemical properties of amino acids, proteins, and DNA, which are essential biological molecules. It covers the amphoteric nature of amino acids, the formation of peptide links in proteins, and the role of hydrogen bonding in DNA structure and enzyme function.

Organic synthesis (A-level only)

Organic synthesis involves the design and execution of multi-step reaction sequences to produce target organic compounds. Students must apply their knowledge of functional group transformations and reaction mechanisms to devise efficient synthetic routes of up to four steps.

Nuclear magnetic resonance spectroscopy (A-level only)

Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique used to determine the structure of organic compounds by identifying the chemical environments of 13C and 1H atoms. It utilizes the chemical shift on a delta scale and integration data to map molecular structure, while spin-spin splitting patterns provide information about adjacent non-equivalent protons.

Chromatography (A-level only)

Chromatography is an analytical technique used to separate and identify components within a mixture based on their differential distribution between a stationary phase and a moving phase. The topic covers three primary methods: thin-layer chromatography (TLC), column chromatography (CC), and gas chromatography (GC), emphasizing the balance between solubility and retention.

Alkanes

Alkanes are saturated hydrocarbons that serve as the primary constituents of crude oil and are widely utilized as fuels. This topic covers their physical separation through fractional distillation, chemical modification via cracking, combustion processes, and the free-radical substitution mechanism of chlorination.

Halogenoalkanes

Halogenoalkanes are organic compounds containing a carbon-halogen bond, which makes them significantly more reactive than alkanes. This topic covers their nucleophilic substitution and elimination reactions, the mechanisms involved, and the environmental impact of chlorofluorocarbons (CFCs) on the ozone layer.

Alkenes

Alkenes are unsaturated hydrocarbons characterized by a carbon-carbon double bond, which acts as a center of high electron density. This structural feature makes them susceptible to electrophilic attack, leading to various addition reactions and the formation of commercially important addition polymers.

Alcohols

This topic covers the production of alcohols via hydration of alkenes and fermentation of glucose, including the environmental implications of biofuels. It also details the classification of alcohols as primary, secondary, or tertiary, their oxidation reactions, and their dehydration to form alkenes.

Organic analysis

This topic covers the analytical techniques used to identify organic compounds and their functional groups. It integrates chemical test-tube reactions with spectroscopic methods, specifically mass spectrometry and infrared spectroscopy, to deduce molecular structures.

Optical isomerism (A-level only)

Optical isomerism is a form of stereoisomerism arising from chirality in molecules, specifically those containing a single chiral centre. This topic explores how enantiomers exist as non-superimposable mirror images that differ in their effect on plane-polarised light, and the formation of optically inactive racemic mixtures.

Aldehydes and ketones (A-level only)

This topic focuses on the chemistry of the carbonyl group found in aldehydes and ketones. It covers their oxidation, reduction, and nucleophilic addition reactions, including the formation of hydroxynitriles and the stereochemical implications of these additions.

Carboxylic acids and derivatives (A-level only)

This topic covers the chemistry of carboxylic acids, esters, and their derivatives, including acyl chlorides, acid anhydrides, and amides. It focuses on their structures, chemical properties, and nucleophilic addition-elimination reactions, as well as the industrial production of esters, biodiesel, and soap.