NCERT Class 11 Chemistry Chemical Bonding and Molecular Structure

Read and download NCERT Class 11 Chemistry Chemical Bonding and Molecular Structure chapter in NCERT book for Class 11 Chemistry. You can download latest NCERT eBooks for 2021 chapter wise in PDF format free from Studiestoday.com. This Chemistry textbook for Class 11 is designed by NCERT and is very useful for students. Please also refer to the NCERT solutions for Class 11 Chemistry to understand the answers of the exercise questions given at the end of this chapter

Chemical Bonding And Molecular Structure Class 11 Chemistry NCERT

Class 11 Chemistry students should refer to the following NCERT Book chapter Chemical Bonding And Molecular Structure in standard 11. This NCERT Book for Grade 11 Chemistry will be very useful for exams and help you to score good marks

Chemical Bonding And Molecular Structure NCERT Class 11

CHEMICAL BONDING AND

MOLECULAR STRUCTURE

Matter is made up of one or different type of elements. Under normal conditions no other element exists as an independent atom in nature, except noble gases. However, a group of atoms is found to exist together as one species having characteristic properties. Such a group of atoms is called a molecule. Obviously there must be some force which holds these constituent atoms together in the molecules. The attractive force which holds various constituents (atoms, ions, etc.) together in different chemical species is called a chemical bond.

Since the formation of chemical compounds takes place as a result of combination of atoms of various elements in different ways, it raises many questions. Why do atoms combine? Why are only certain combinations possible? Why do some atoms combine while certain others do not? Why do molecules possess definite shapes? To answer such questions different theories and concepts have been put forward from time to time. These are Kössel-Lewis approach, Valence Shell Electron Pair Repulsion (VSEPR) Theory, Valence Bond (VB) Theory and Molecular Orbital (MO) Theory.

The evolution of various theories of valence and the interpretation of the nature of chemical bonds have closely been related to the developments in the understanding of the structure of atom, the electronic coniguration of elements and the periodic table. Every system tends to be more stable and bonding is nature’s way of lowering the energy of the system to attain stability.

4.1 KÖSSEL-LEWIS APPROACH TO CHEMICAL BONDING

In order to explain the formation of chemical bond in terms of electrons, a number of attempts were made, but it was only in 1916 when Kössel and Lewis succeeded independently in giving a satisfactory explanation. They were the first to provide some logical explanation of valence which was based on the inertness of noble gases. Lewis pictured the atom in terms of a positively charged ‘Kernel’ (the nucleus plus the inner electrons) and the outer shell that could accommodate a maximum of eight electrons. He, further assumed that these eight electrons occupy the corners of a cube which surround the ‘Kernel’. Thus the single outer shell electron of sodium would occupy one corner of the cube, while in the case of a noble gas all the eight corners would be occupied. This octet of electrons, represents a particularly stable electronic arrangement.

Lewis postulated that atoms achieve the stable octet when they are linked by chemical bonds. In the case of sodium and chlorine, this can happen by the transfer of an electron from sodium to chlorine thereby giving the Na+ and Cl ions. In the case of other molecules like Cl2, H2, F2, etc., the bond is formed by the sharing of a pair of electrons between the atoms. In the process each atom attains a stable outer octet of electrons.

Lewis Symbols: In the formation of a molecule, only the outer shell electrons take part in chemical combination and they are known as valence electrons. The inner shell electrons are well protected and are generally not involved in the combination process.

G.N. Lewis, an American chemist introduced simple notations to represent valence electrons in an atom. These notations are called Lewis symbols. For example, the Lewis symbols for the elements of second period are as under:


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Chapter 1 Some Basic Concepts of Chemistry
NCERT Class 11 Chemistry Some Basic Concepts Of Chemistry
Chapter 2 Structure of Atom
NCERT Class 11 Chemistry Structure of Atom
Chapter 3 Classification of Elements and Periodicity in Properties
NCERT Class 11 Chemistry Classification of Elements and Periodicity In Properties
Chapter 4 Chemical Bonding and Molecular Structure
NCERT Class 11 Chemistry Chemical Bonding and Molecular Structure
Chapter 5 States of Matter
NCERT Class 11 Chemistry State Of Matter
Chapter 6 Thermodynamics
NCERT Class 11 Chemistry Thermodynamics
Chapter 7 Equilibrium
NCERT Class 11 Chemistry Equilibrium
Chapter 8 Redox Reactions
NCERT Class 11 Chemistry Redox Reactions
Chapter 9 Hydrogen
NCERT Class 11 Chemistry Hydrogen
Chapter 10 The s-Block Elements
NCERT Class 11 Chemistry The s Block Elements
Chapter 11 The p-Block Elements
NCERT Class 11 Chemistry The p Block Elements
Chapter 12 Organic Chemistry – Some Basic Principles & Techniques
NCERT Class 11 Chemistry Organic Chemistry Some Basic Priciples and Techniques
Chapter 13 Hydrocarbons
NCERT Class 11 Chemistry Hydrocarbons
Chapter 14 Environmental Chemistry
NCERT Class 11 Chemistry Environmental Chemistry
Other Chapters
NCERT Class 11 Chemistry Lab Manual Purification and Criteria of Purity
NCERT Class 11 Chemistry Lab Manual Systematics Qualitative Analysis
NCERT Class 11 Chemistry Lab Manual Basic Laboratory Techniques
NCERT Class 11 Chemistry Lab Manual Titrimetric Analysis
NCERT Class 11 Chemistry Lab Manual Chemical Equilibrium Ionic Equilibrium
NCERT Class 11 Chemistry Lab Manual Information about Investigatory Projects
NCERT Class 11 Chemistry Lab Manual Introduction
NCERT Class 11 Chemistry Lab Manual ph and ph change in Aqueous Solutions
Part I Answer to Some Selected Problems
NCERT Class 11 Chemistry Answer of Some Selected Problems
Part I Appendices
NCERT Class 11 Chemistry Appendix 2 Elements Their Atomic Number and Molar Mass
NCERT Class 11 Chemistry Appendix 3
NCERT Class 11 Chemistry Appendix 4 Physical Constants
NCERT Class 11 Chemistry Appendix 5 Some Useful Conversion Factores
NCERT Class 11 Chemistry Appendix 6 Thernodynamic Data at 298 K
NCERT Class 11 Chemistry Appendix 7 Standard Potentials at 298 K in Electrochemical order
NCERT Class 11 Chemistry Appendix 1
Part II Answer to Some Selected Problems
NCERT Class 11 Chemistry Answer to Some Selected Problems

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