ISC Chemistry Class 11 Syllabus 2025-26

Theory paper is of 3 hours duration and 70 marks. There are 14 units in the syllabus.

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1. Some Basic Concepts of Chemistry

General introduction: Importance and scope of chemistry.

Study of matter. Understanding laws of chemical combination. Dalton's atomic theory: concept of elements, atoms and molecules.

Isotopic (atomic) and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula. Stoichiometry and calculations based on chemical reactions.

2. Structure of Atom

Discovery of fundamental particles electron, proton and neutron), atomic number, isotopes and isobars. Thomson's model and its limitations. Rutherford's experimental model and its limitations. Dual nature of matter and light. Bohr's atomic model and its limitations (de Broglie's equation, Heisenberg’s uncertainty principle), concept of shells, subshells, orbitals.

Quantum numbers, shapes of s, p and d orbitals. Rules for filling electrons in orbitals - aufbau principle, Pauli's exclusion principle and Hund's rule of maximum multiplicity. Electronic configuration of atoms, stability of half- filled and completely filled orbitals.

3. Classification of Elements and Periodicity in Properties

Significance of classification; study of Mendeleev’s periodic law and its limitations; Modern Periodic Law and the present form of periodic table leading to periodic trends in properties of elements - atomic radii, ionic radii, valency, ionisation enthalpy, electron gain enthalpy, electronegativity. Nomenclature of elements with atomic number greater than 100.

4. Chemical Bonding and Molecular Structure

Valence electrons, ionic bond character, covalent bond of ionic bond, covalent bond, bond parameters, lewis structure, polar character of covalent bond, VSEPR theory, geometry of covalent molecules, valence bond theory, concept of hybridisation involving s, p and d orbitals and shapes of some simple molecules.

Coordinate bond. Molecular orbital theory of homonuclear diatomic molecules (qualitative idea only). Resonance and hydrogen bond.

5. States of Matter: Gases and Liquids

States of matter and their characteristic properties to establish the concept of the molecule. Boyle's law, Charles law, Gay Lussac's law, Avogadro's law, Avogadro’s number, ideal behaviour of gases and derivation of ideal gas equation. Kinetic Theory of gases, kinetic energy and molecular speeds (elementary idea).

Deviation from ideal behaviour, van der Waal’s equation, liquefaction of gases, critical temperature. Liquid state - vapour pressure, viscosity and surface tension (qualitative idea only, no mathematical derivations).

6. Chemical Thermodynamics

(i) Introduction, concepts, types of system, surroundings, extensive, intensive properties and state functions.

(ii) First Law of Thermodynamics and its significance, work, heat, internal energy, enthalpy (∆U or ∆E and ∆H), heat capacity and specific heat. Hess's law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomisation, sublimation, phase transition, ionisation, solution and dilution.

(iii) Second Law of Thermodynamics and its significance, spontaneity of a chemical change; Entropy, Free Energy. Inadequacy of First Law and need for Second Law; Ideas about reversible (recapitulation), spontaneous and non-spontaneous processes.

(iv) Third Law of Thermodynamics - statement only.

7. Equilibrium

(i) Chemical Equilibrium

Introduction of physical and chemical equilibrium and its characteristics

Dynamic nature of equilibrium, law of mass action, equilibrium constant and factors affecting equilibrium. Le Chatelier's principle and its applications.

(ii) Ionic equilibrium

Introduction, electrolyte (strong and weak), non-electrolyte, ionisation, degree of ionisation of polybasic acids, acid strength, concept of pH, pH indicators, buffer solution, common ion effect (with illustrative examples). Henderson equation, hydrolysis of salts, solubility and solubility product.

8. Redox Reactions

Concept of oxidation and reduction, redox reactions, oxidation number, change in oxidation number, balancing redox reactions (in terms of loss and gain of electrons). Applications of redox in various types of chemical reactions.

9. Hydrogen

Hydrogen and its compounds: hydrides, water, heavy water, hydrogen peroxide.

10. s-Block Elements

(Alkali and Alkaline Earth Metals)

(i) Group 1 and 2 elements

(ii) Preparation and properties of some important compounds.

11. Some p-Block Elements

(i) Group 13 Elements

(ii) Preparation and properties of some important compounds, borax, boric acid, boron hydrides, aluminium: Reactions with acids and alkalies. Lewis acid character of boron halides; amphoteric nature of aluminium, alums.

(iii) Group 14 Elements

(iv) Some important compounds; oxides of carbon and silicon, silicon carbide, silicon tetra chloride, silicones, silicates and zeolites.

12. Organic Chemistry - Some Basic Principles and Techniques

General introduction, classification and IUPAC nomenclature of organic compounds and isomerism.

Methods of purification, qualitative and quantitative analysis. Electron displacement in a covalent bond: inductive effect, electromeric effect, resonance and hyperconjugation.

Homolytic and heterolytic bond fission of a covalent bond: free radicals, carbocations, carbanions, electrophiles and nucleophiles, types of organic reactions.

13. Hydrocarbons

Classification of Hydrocarbons

I. Aliphatic Hydrocarbons

(i) Alkanes - Nomenclature, isomerism, conformation (methane and ethane), physical properties, chemical properties including free radical mechanism of halogenation, combustion and pyrolysis.

(ii) Alkenes - Nomenclature, structure of double bond (ethene), isomerism; methods of preparation; physical properties, chemical properties; addition of hydrogen, halogen, water, hydrogen halides (Markownikoff's addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition.

(iii) Alkynes - Nomenclature, structure of triple bond (ethyne), methods of preparation; physical properties,  chemical properties: acidic character of alkynes, addition reactions - hydrogen, halogens, hydrogen halides and water.

II. Aromatic Hydrocarbons

Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Crafts alkylation and acylation, directive influence of functional group in monosubstituted benzene. Carcinogenicity and toxicity.

14. Environmental Chemistry

Types of environmental pollution (air, water and soil pollution); various types of pollutants: smog, acid rain; effects of depletion of ozone layer, greenhouse effect and global warming. Pollution due to industrial wastes, green chemistry as an
alternative tool for reducing pollution; strategies for control of environmental pollution.