CLASS-XI NCERT CHEMISTRY

UNIT-1: Some Basic Concepts of Chemistry
13 Topics | 2 Quizzes
1.0 Introduction
1.1 Importance of Chemistry
1.2 Nature of Matter
1.3 Properties of Matter and their Measurement
1.4 Uncertainty in Measurement
1.5 Laws of Chemical Combinations
1.6 Dalton’s Atomic Theory
1.7 Atomic and Molecular Masses
1.8 Mole Concept and Molar Masses
1.9 Percentage Composition
1.10 Stoichiometry and Stoichiometric Calculations
1.11 Summary
1.12 Exercise Problems and Solutions
NCERT Exemplar MCQs
NEET PYQs
UNIT-2: Structure of Atom
9 Topics | 2 Quizzes
2.0 Introduction
2.1 Discovery of Sub-atomic Particles
2.2 Atomic Models
2.3 Developments Leading to the Bohr’s Model of Atom
2.4 Bohr’s Model for Hydrogen Atom
2.5 Towards Quantum Mechanical Model of the Atom
2.6 Quantum Mechanical Model of Atom
2.7 Summary
2.8 Exercise Problems and Solutions
NCERT Exemplar MCQs
NEET PYQs
UNIT-3: Classification of Elements and Periodicity in Properties
10 Topics | 2 Quizzes
3.0 Introduction
3.1 Why do we Need to Classify Elements?
3.2 Genesis of Periodic Classification
3.3 Modern Periodic Law and the Present Form of the Periodic Table
3.4 Nomenclature of Elements with Atomic Numbers > 100
3.5 Electronic Configurations of Elements and the Periodic Table
3.6 Electronic Configurations and Types of Elements: s-, p-, d-, f- Blocks
3.7 Periodic Trends in Properties of Elements
3.8 Summary
3.9 Exercise Problems and Solutions
NCERT Exemplar MCQs
NEET PYQs
UNIT-4: Chemical Bonding and Molecular Structure
12 Topics | 2 Quizzes
4.0 Introduction
4.1 Kossel- Lewis Approach to Chemical Bonding
4.2 Ionic or Electrovalent Bond
4.3 Bond Parameters
4.4 The Valence Shell Electron Pair Repulsion
4.5 Valence Bond Theory
4.6 Hybridisation
4.7 Molecular Orbital Theory
4.8 Bonding in Some Homonuclear Diatomic Molecules
4.9 Hydrogen Bonding
4.10 Summary
4.11 Exercise Problems and Solutions
NCERT Exemplar MCQs
NEET PYQs
UNIT-5: Thermodynamics
10 Topics | 2 Quizzes
5.0 Introduction
5.1 Thermodynamic Terms
5.2 Applications
5.3 Measurement of ΔU and ΔH: Calorimetry
5.4 Enthalpy Change, ΔrH of a Reaction – Reaction Enthalpy
5.5 Enthalpies for Different Types of Reactions
5.6 Spontaneity
5.7 Gibbs Energy Change and Equilibrium
5.8 Summary
5.9 Exercise Problems and Solutions
NCERT Exampler Questions
NEET PYQs
UNIT-6: Equilibrium
16 Topics | 2 Quizzes
6.0 Introduction
6.1 Equilibrium in Physical Processes
6.2 Equilibrium in Chemical Processes – Dynamic Equilibrium
6.3 Law of Chemical Equilibrium and Equilibrium Constant
6.4 Homogeneous Equilibria
6.5 Heterogeneous Equilibria
6.6 Applications of Equilibrium Constants
6.7 Relationship between Equilibrium Constant K Reaction Quotient Q and Gibbs Energy G
6.8 Factors Affecting Equilibria
6.9 Ionic Equilibrium in Solution
6.10 Acids, Bases and Salts
6.11 Ionization of Acids and Bases
6.12 Buffer Solutions
6.13 Solubility Equilibria of Sparingly Soluble Salts
6.14 Summary
6.15 Exercise Problems and Solutions
NCERT Exampler Questions
NEET PYQs
UNIT-7: Redox Reaction
7 Topics | 2 Quizzes
7.0 Introduction
7.1 Classical Idea of Redox Reactions-Oxidation and Reduction Reactions
7.2 Redox Reactions in Terms of Electron Transfer Reactions
7.3 Oxidation Number
7.4 Redox Reactions and Electrode Processes
7.5 Summary
7.6 Exercise Problems and Solutions
NCERT Exampler
NEET PYQs
UNIT-8: Organic Chemistry – Some Basic Principles and Techniques
13 Topics | 2 Quizzes
8.0 Introduction
8.1 General Introduction
8.2 Tetravalence of Carbon: Shapes of Organic Compounds
8.3 Structural Representations of Organic Compounds
8.4 Classification of Organic Compounds
8.5 Nomenclature of Organic Compounds
8.6 Isomerism
8.7 Fundamental Concepts in Organic Reaction Mechanism
8.8 Methods of Purification of Organic Compounds
8.9 Qualitative Analysis of Organic Compounds
8.10 Quantitative Analysis
8.11 Summary
8.12 Exercise Problems and Solutions
NCERT Exemplar Questions
NEET PYQs
UNIT-9: Hydrocarbons
9 Topics | 2 Quizzes
9.0 Introduction
9.1 Classification
9.2 Alkanes
9.3 Alkenes
9.4 Alkynes
9.5 Aromatic Hydrocarbon
9.6 Carcinogenicity and Toxicity
9.7 Summary
9.8 Exercise Problems and Solutions
NCERT Exemplar
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8.6 Isomerism

CLASS-XI NCERT CHEMISTRY UNIT-8: Organic Chemistry – Some Basic Principles and Techniques 8.6 Isomerism

The phenomenon of existence of two or more compounds possessing the same molecular formula but different properties is known as isomerism. Such compounds are called as isomers. The following flow chart shows different types of isomerism.

Structural Isomerism

Compounds having the same molecular formula but different structures (manners in which atoms are linked) are classified as structural isomers. Some typical examples of different types of structural isomerism are given below:

(i) Chain isomerism: When two or more compounds have similar molecular formula but different carbon skeletons, these are referred to as chain isomers and the phenomenon is termed as chain isomerism. For example, \(\mathrm{C}_5 \mathrm{H}_{12}\) represents three compounds:

(ii) Position isomerism: When two or more compounds differ in the position of substituent atom or functional group on the carbon skeleton, they are called position isomers and this phenomenon is termed as position isomerism. For example, the molecular formula \(\mathrm{C}_3 \mathrm{H}_8 \mathrm{O}\) represents two alcohols:

(iii) Functional group isomerism: Two or more compounds having the same molecular formula but different functional groups are called functional isomers and this phenomenon is termed as functional group isomerism. For example, the molecular formula \(\mathrm{C}_3 \mathrm{H}_6 \mathrm{O}\) represents an aldehyde and a ketone:

(iv) Metamerism: It arises due to different alkyl chains on either side of the functional group in the molecule. For example, \(\mathrm{C}_4 \mathrm{H}_{10} \mathrm{O}\) represents methoxypropane \(\left(\mathrm{CH}_3 \mathrm{OC}_3 \mathrm{H}_7\right)\) and ethoxyethane \(\left(\mathrm{C}_2 \mathrm{H}_5 \mathrm{OC}_2 \mathrm{H}_5\right)\).

Stereoisomerism

The compounds that have the same constitution and sequence of covalent bonds but differ in relative positions of their atoms or groups in space are called stereoisomers. This special type of isomerism is called as stereoisomerism and can be classified as geometrical and optical isomerism.

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