Course Content
Section Name Topic Name 3 Classification of Elements and Periodicity in Properties 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
Section Name Topic Name 7 Equilibrium 7.1 Equilibrium in Physical Processes 7.2 Equilibrium in Chemical Processes – Dynamic Equilibrium 7.3 Law of Chemical Equilibrium and Equilibrium Constant 7.4 Homogeneous Equilibria 7.5 Heterogeneous Equilibria 7.6 Applications of Equilibrium Constants 7.7 Relationship between Equilibrium Constant K, Reaction Quotient Q and Gibbs Energy G 7.8 Factors Affecting Equilibria 7.9 Ionic Equilibrium in Solution 7.10 Acids, Bases and Salts 7.11 Ionization of Acids and Bases 7.12 Buffer Solutions 7.13 Solubility Equilibria of Sparingly Soluble Salts
Section Name Topic Name 10 The s-Block Elements 10.1 Group 1 Elements: Alkali Metals 10.2 General Characteristics of the Compounds of the Alkali Metals 10.3 Anomalous Properties of Lithium 10.4 Some Important Compounds of Sodium 10.5 Biological Importance of Sodium and Potassium 10.6 Group 2 Elements : Alkaline Earth Metals 10.7 General Characteristics of Compounds of the Alkaline Earth Metals 10.8 Anomalous Behaviour of Beryllium 10.9 Some Important Compounds of Calcium 10.10 Biological Importance of Magnesium and Calcium
Section Name Topic Name 12 Organic Chemistry – Some Basic Principles and Techniques 12.1 General Introduction 12.2 Tetravalence of Carbon: Shapes of Organic Compounds 12.3 Structural Representations of Organic Compounds 12.4 Classification of Organic Compounds 12.5 Nomenclature of Organic Compounds 12.6 Isomerism 12.7 Fundamental Concepts in Organic Reaction Mechanism 12.8 Methods of Purification of Organic Compounds 12.9 Qualitative Analysis of Organic Compounds 12.10 Quantitative Analysis
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About Lesson


It is existence of compounds in two or more forms, having same molecular formula but different physical and chemical properties.

It is basically of two types:

  • Structural
  • Stereoisomerism

Structural isomerism: Differ in arrangement            of atoms within molecule.         

Stereoisomerism: Differ in arrangement of atom in space.

The structural isomerism type:

  • Chain
  • Position
  • Functional
  • Meta-merism
  • Tauto-merism

The different types of stereoisomerism are:

  • Geometrical
  • Optical
  • conformational

Let us study first structural isomerism types :

  1. Chain isomerism– The compounds that have same molecular formula ,but different arrangement of atoms within the chain.
Organic Chemistry Class 11th Chapter 12 Notes and NCERT Solution.

Position isomerism: The compounds with same molecular formula, but differ in position of substituent, side chain or functional groups.

Organic Chemistry Class 11th Chapter 12 Notes and NCERT Solution.
Organic Chemistry

Functional isomerism: The compounds with same molecular formula but differ in type of functional group and also in physical and chemical properties.

  1. Metamerism: The compounds that have same molecular formula ,but differ in number of carbon atoms around functional group.

 It is shown by functional groups like ether, esters, ketones.

Organic Chemistry Class 11th Chapter 12 Notes and NCERT Solution.
  1. Tautomerism: In this simultaneous movement of π electron cloud and Hydrogen take place. Most common tautomerism is keto – enol tautomerism.
Organic Chemistry Class 11th Chapter 12 Notes and NCERT Solution.

let us study stereo isomerism now   

In it the compounds have same molecular formula , but different arrangement of atoms in three-dimensional space.

It is of three types:

  1. Geometrical : It arises due to restricted rotation around C=C bond.

Conditions required are :

  1. Presence of C=C bond.
  2. The two groups attached to carbon atoms must be different.
Organic Chemistry Class 11th Chapter 12 Notes and NCERT Solution.
Organic Chemistry


Organic Chemistry
  • As far as stability is concerned, more bulky is the group, more is the Stearic hindrance.
  • Stearic hindrance which creates obstruction in rotation therefore, less is the stability.

      But-2-ene> Pent-2-ene-Hex>3-ene                 

CONFORMATIONAL ISOMERISM: It exists in Alkanes (C-C). It is due to full rotation around C-C single bond.

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