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


There were so many factors, phenomenon that lead to the failure of Rutherford model:

  1. Dual nature of matter
  2. Atomic spectra

But before studying Bohr model, we need to learn electromagnetic radiations.

Newton said the corpuscles of light possess wave nature of light.

It was able to explain reflection, refraction etc. But failed to explain phenomenon of interface or diffraction. So, particle nature of light was considered.

Let us study about dual nature. It is electromagnetic theory, which was given by Huygens.This proved wave like character of

Light and tells us about wave motion. Wave motion is like if you throw stones, you will see a ripple that is wave.

Electromagnetic theory: According to this theory

  1. Energy is emitted or absorbed continuously in the form of radiant energy.
  2. These radiations consist of electric and magnetic field acting perpendicular to the direction of propagation of wave.
  3. These waves can travel through medium as well as through vacuum.
  4. The radiations travel with speed =3×108m/sec.
Class 11th Chemistry Chapter 2 Structure of Atom Notes and NCERT Solution
structure of atom
  • Frequency: number of waves produced in one second.
  • Units Used:- sec-1, Hertz
  • Velocity of light: It is distance travelled with respect to time in any direction.
  • Units Used:- m/sec
  • Amplitude: maximum displacement of particle from its mean position.
  • Units Used:- m or cm
  • Wave number: number of waves in 1cm length.
Class 11th Chemistry Chapter 2 Structure of Atom Notes and NCERT Solution

Black body radiation and Photoelectric effect ( Structure of Atom )

Particle nature of Electromagnetic radiations :There were two important phenomenon that couldn’t be explained by considering Light with  wave character:

The phenomenon is:

  • Black body radiation
  • Photoelectric effect

Lets first study about the nature of these phenomenon:

  1. Black body radiation: Black body is defined as perfect emitter and absorber of light.

For example, whenever we heat an Iron ball like objects, on heating they become first Red, then Orange, then Yellow and at very high temperature they become White.

  1. Photoelectric effect

It is the ejection of electrons from metal surface when light of suitable wavelength strikes the metal surface.

The apparatus set to demonstrate this effect is given below:

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