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
Class 11th Chemistry Online Class: Elevate Your CBSE Board Success
About Lesson

Hydrogen bonding

Hydrogen bond

Hydrogen bond is formed when hydrogen is attached to some electronegative element like O, N and F. It forma a special bond with them   called as hydrogen bond.

Types of Hydrogen bond

  • Intermolecular H bond.
  • Intra-molecular H bond.

Intermolecular Hydrogen bond: It is a bond formed between two different molecules.

Example: H-F—–H-F—-H-F

Intra-molecular Hydrogen bond: A bond that is formed within the molecule.

Consequences of Hydrogen bonding:

  • They exist as associated molecules.
  • Boiling points of compound having H-bond are higher as they have extra bonds in them.
  • They generally exist as liquids.

Hydrogen bonding in ice and water

The structure of Ice is given below :

Class 11th Chemical Bonding and Molecular Structure
Chemical Bonding
  • In it each oxygen atom is linked to 4 Hydrogen.
  • Two Hydrogen are linked by covalent bond and 2 Hydrogen by Hydrogen bonds.
  • It forms network and space between is hollow.
  • That is why; the ice is lighter due to hollow space.
  • Therefore, ice floats on water.
  • As we know, ice has high density so it should sink
  • But, in actual practice it does not sink.
  • Due to presence of hydrogen bonding in it, this makes the structure of ice hollow.
  • Therefore, density decreases.

Water has maximum density at 4 degree Celsius:

This is seen because at zero degrees Celsius the water is ice. Now, if we start increasing its temperature gradually, we see that the cage of ice starts breaking. Due to it, hollow space starts getting filled. H-bonds break therefore, density increases.

At 4 degree Celsius, kinetic energy of molecules starts increasing and they start moving away due to which density decreases.

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