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




On the earth Hydrogen exists as H2 molecule (dihydrogen). It constitutes to 10 % mass of universe. Hydrogen exit in many substances like carbohydrates, hydrocarbons etc. It is actually 3rd most abundant element

Characteristics of Hydrogen

Similarities with alkali metals – Its similarities with alkali metals are given below

Same number of valence electrons -1

Like alkali metals it has electropositive character

Oxidation state =+1, example is in HCl

It is strong reducing agent.

For Example: – Fe2O3    +      3H2 à      2Fe + 3H2O

                       Ferric Oxide   Hydrogen  Iron      Water

Difference with alkali metals –

Ionisation energy of Hydrogen is high as compared to alkali metals Ionisation Energy of alkali is less. 
Shows non -metallic behaviour metallic behaviour
Diatomic molecule as gas monoatomic
Hydrogen mostly form covalent bonds Ionic bonds
Class 11th Chemistry Hydrogen Notes and NCERT Solution

Similarities with Halogens –

  1. Hydrogen has only Ionisation energy less than noble gases.
  2. Ionisation energies of Hydrogen is 1312 kJmol-1 close to chlorine.
  3. Oxidation state of Hydrogen is -1 in many compounds.
  4. H2 is diatomic.
  5. Hydrogen is non-metallic and exists in gaseous state.

Differences with Halogen –

Hydrogen has fewer tendencies to accept electron.      They have more tendencies   to accept electron. 
It has no unshared electron pairs. They have unshared electron
Their oxide is neutral Their oxide is acidic
Class 11th Chemistry Hydrogen Notes and NCERT Solution


  • H2 Preparation (in laboratory)

It is formed in labs by reacting granulated Zinc with dilute hydrochloric acid . The   apparatus used is shown in figure:

Class 11th Chemistry Hydrogen Notes and NCERT Solution

Out of all methods : Different methods are used to yield hydrogen as shown :

By Pertoluem Method 77% 

By Electrolysis Method 18%

By other sources 1%

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