Chapter 4 - Chemical Bonding and Molecular Structure

In this chapter, you will study chemical bonding and molecular structure in detail. You already know what you mean by an atom and a molecule. There is also something known as a chemical bond.

A chemical bond is a bond built with the attractive forces between atoms, ions or molecules leading to the formation of chemical compounds. In this chapter, you’ll learn about chemical bonding as suggested by various scientists such as KÖssel-Lewis. You’ll also come across the octet rule and its drawbacks. Further, it is interesting to study about the formation of different types of chemical bonds, the VSEPR theory, the concept of valence bond and covalent bond, directional properties of covalent bonds, and much more.

Thus, an in-depth study of Class 11 Chemistry NCERT Solutions Chapter 4 will give you a good understanding of chemical bonding and molecular structure.

Let’s take a look at topics and sub-topics of Class 11 Chemistry Chapter 4 – Chemical Bonding and Molecular Structure.

4.1 Kössel-Lewis Approach to Chemical Bonding

4.1.1 Octet Rule

4.1.2 Covalent Bond

4.1.3 Lewis Representation of Simple Molecules (the Lewis Structures)

4.1.4 Formal Charge

4.1.5 Limitations of the Octet Rule

4.2 Ionic or Electrovalent Bond

4.2.1 Lattice Enthalpy

4.3 Bond Parameters

4.3.1 Bond Length

4.3.2 Bond Angle

4.3.3 Bond Enthalpy

4.3.4 Bond Order

4.3.5 Resonance Structures

4.3.6 Polarity of Bonds

4.4 The Valence Shell Electron Pair Repulsion (VSEPR) Theory

4.5 Valence Bond Theory

4.5.1 Orbital Overlap Concept

4.5.2 Directional Properties of Bonds

4.5.3 Overlapping of Atomic Orbitals

4.5.4 Types of Overlapping and Nature of Covalent Bonds

4.5.5 Strength of Sigma and pi Bonds

4.6 Hybridisation

4.6.1 Types of Hybridisation

4.6.2 Other Examples of sp3, sp2 and sp Hybridisation

4.6.3 Hybridisation of Elements involving d Orbitals

4.7 Molecular Orbital Theory

4.7.1 Formation of Molecular Orbitals Linear Combination of Atomic Orbitals (LCAO)

4.7.2 Conditions for the Combination of Atomic Orbitals

4.7.3 Types of Molecular Orbitals

4.7.4 Energy Level Diagram for Molecular Orbitals

4.7.5 Electronic Configuration and Molecular Behaviour

4.8 Bonding in Some Homonuclear Diatomic Molecules

4.9 Hydrogen Bonding

4.9.1 Cause of Formation of Hydrogen Bond

4.9.2 Types of H-Bonds

In Class 11 Chemistry Chapter 4, you will learn –

Section 4.1 – In this section, you’ll learn about some interesting facts stated by Kössel related to chemical bonding. You’ll also come across various new terms such as group valence, valence electrons, Lewis symbols, the significance of Lewis symbols, electrovalent bond, the electronic theory of chemical bonding, and more.

Section 4.2 – In this section, you will study about ionic or electrovalent bond and explore the concept of Lattice Enthalpy.

Section 4.3 – In this section, you’ll learn about various bond parameters such as the bond length, bond angle, bond enthalpy, bond order, resonance structures and polarity of bonds. You’ll also learn some related terms to these parameters.

Section 4.4 – In this section, you’ll acquire knowledge about the main postulates of VSEPR theory. You’ll also come across the geometry of molecules, in which the central Atom has no lone pair of electrons; shape (geometry) of some simple molecules/ions with central ions having one or more lone pairs of electrons(E); and shapes of molecules containing bond pair and lone pair.

Section 4.5 – In this section, you’ll study the Valence Bond theory introduced by Heitler and London and further developed by Pauling and others.

Section 4.6 – In this section, you’ll study about what hybridisation is, some important feature of hybridisation, hybrid orbitals, necessary conditions for hybridisation, types of hybridisation and examples of sp3, sp2 and sp hybridisation.

Section 4.7 – In this section, you’ll learn some interesting features of the Molecular orbital (MO) theory developed by F. Hund and R.S. Mulliken in 1932.

Section 4.8 – In this section, you’ll study about the bonding in some homonuclear diatomic molecules such as Hydrogen molecule (H2 ), Helium molecule (He2 ), Lithium molecule (Li2 ), Carbon molecule (C2 ) and Oxygen molecule (O2 ).

Section 4.9 – In this section, you’ll acquire knowledge about hydrogen bonding, the causes of the formation of hydrogen bonding and two types of H-Bond.

In this chapter, you are provided with several examples with their solutions for a clear understanding of Chemical Bonding and Molecular Structure. To know more about NCERT Solutions for Class 11 Chemistry Chapter 4, you should explore the exercises mentioned in this chapter. You can also download the NCERT Solutions for Class 11 Chemistry Chapter 4 PDF, solved by our science experts.