NCERT Solutions Class 11 Chemistry Chapter 4

NCERT Solutions for Class 11 Chemistry Chapter 4 – Chemical Bonding and Molecular Structure 

Chemistry is the study of substances and is a field that involves everything around us. According to the American Chemical Society, all that can be seen, touched, tasted, smelled, and heard has chemistry and chemicals involved in it. To help students in preparing for their exams, Extramarks offers NCERT Solutions for Class 11 Chemistry Chapter 4. They can be accessed easily from the link below 

Access NCERT Solutions for Class 11 Chemistry Chapter – 4 Chemical Bonding and Molecular Structure 

NCERT Exercise

Limitations of the Octet Theory:  

Octet theory has the following limitations:

  • It applies only to atoms in their ground state.
  • It does not take into account the nature of chemical bonding between atoms.
  • It does not take into account the number of electrons in an atom.

Chapter 4 explains all these limitations of Octet theory in detail.

NCERT Solutions for Class 11 Chemistry Chapter – 4 Chemical Bonding and Molecular Structure 

Chapter 4 of NCERT Class 11 Chemistry covers the formation of chemical bonds, Lewis dot symbols, and other concepts. The chapter has exercise questions at the end to help students gauge their understanding of the concepts. NCERT Solutions for Chapter 4 enables students to get accurate answers to the practise questions listed at the end of the chapter. 

NCERT Class 11 Chemistry Chapter 4 – Question 1 

Que. Explain the formation of a chemical bond.

Ans. A chemical bond is an attractive force holding the atoms, ions and other constituents together in a chemical species. The formation of a chemical bond can be related to the tendency of a system for attaining stability. The inertness of noble gases is due to their fully filled outermost orbitals. Thus, it was assumed that elements with incomplete outermost shells are unstable or reactive. This is why atoms combine with each other to complete their octets or duplets for attaining stable configuration of the nearest noble gas. This can occur by sharing electrons or transfer of one or more electrons from one atom to another. This results in the formation of a chemical bond.

NCERT Class 11 Chemistry Chapter 4 – Question 2 

Que. Write Lewis dot symbols for atoms of following elements: NA, B, Mg, O, Br, and N.

Ans. Since there are two valence electrons in Mg atom, the Lewis dot symbol is – 

There is only one valence electron in an atom of sodium, the Lewis dot symbol is –

There are three valence electrons in Boron atom, the Lewis dot symbol is – 

There are six valence electrons in an atom of oxygen, the Lewis dot symbol is – 

There are five valence electrons in an atom of nitrogen, the Lewis dot symbol is – 

There are seven valence electrons in bromine, the Lewis dot symbol is –

NCERT Class 11 Chemistry Chapter 4 – Question 3 

Que: Write Lewis symbols for the following atoms and ions – 

  • S and S2
  • Al and Al+3
  • H and H-

Ans: S and S2

The number of valence electrons in Sulphur is 6, the Lewis dot symbol is:

The dinegative charge refers that there will be two electrons more along with the six valence electrons, so the Lewis dot symbol of S2 is:

Al and Al+3

The number of valence electrons in aluminium is 3, Lewis dot symbol is:

Al3+ means it has donated its three electrons, Lewis dot symbol is:

[Al]3 

H and H-

The number of valence electrons in hydrogen is 1. Lewis dot symbol is:

H.

The uninegative charge means that one more electron in addition to one valence electron, the Lewis dot symbol is:

NCERT Class 11 Chemistry Chapter 4 – Question 4 

Que. What are the favourable factors for the formation of ionic bonds?

Ans. The transfer of one or more electrons from one atom to another leads to the formation of ionic bonds. The formation is dependent on the ease with which neutral atoms can gain or lose electrons. Also, the formation of a bond is dependent on the lattice energy of the compound formed.

Here are some of the favourable factors for the formation of ionic bond:

  • Low ionisation enthalpy of metal atom
  • High lattice energy of the compound that is formed
  • High electron gain enthalpy of a non-metal atom

NCERT Class 11 Chemistry Chapter 4 – Other Questions 

The other questions focus on the octet rule, ionic bonds, bond order, molecular geometry, resonance, etc. To refer to these concepts and get accurate answers to the questions, students can access NCERT Solutions for Class 11 Chemistry Chapter 4.

NCERT Chemistry Class 11 – Chapter 4 (Chemical Bonding and Molecular Structure) 

The subject of Chemistry includes a topic about Chemical Bonding and Molecular Structure in Chapter 4. The NCERT Solutions for Chapter 4 Chemistry by Extramarks are prepared by subject-matter experts to ensure that students understand the concepts thoroughly, and get accurate answers to the questions given at the end of the chapter.

The Chemistry Class 11 Chapter 4 NCERT Solutions by Extramarks help students prepare for their examination, and can be downloaded at any point in time for free.

Extramarks – A Single Solution for Acquiring Excellence  

Extramarks provides NCERT Solutions Class 11 that have detailed explanations of concepts to help students understand the chapter in a better way. Apart from facilitating them with NCERT Solutions for Class 11 Chemistry Chapter 4, Extramarks also provides learning-aid (subject-wise) for all classes to help the students get a deeper insight into the subject.

Students can download Chemistry Class 11 Chapter 4 NCERT Solutions for free and start their exam prep!

FAQs (Frequently Asked Questions)

The chapter discusses core concepts of molecular structure and chemical bonding. Covalent bonds, ionic bonds, valence electrons, etc. are introduced as a part of this chapter. The students learn about Lewis Structure, the polar character of covalent bonds, the geometry of covalent molecules, valence bond theory, bond parameters, the covalent character of an ionic bond, etc. as well. They will also read about types of chemical equations, balanced chemical equations, combination reactions, displacement reactions, decomposition reactions, rancidity, and corrosion. Furthermore, students will be exposed to hybridisation, s, p, and d orbitals, shapes of molecules, VSEPR theory, etc. as well.

  1. Octet Rule
  • Covalent Bond
  • Lewis Representation of Simple Molecules (The Lewis Structures)
  • Formal Charge
  • Limitations of the Octet Rule
  1. Ionic or Electrovalent Bond
  • Lattice Enthalpy
  1. Bond Parameter
  • Bond Length
  • Bond Angle
  • Bond Enthalpy
  • Bond Order
  • Resonance Structures
  • Polarity of Bonds
  1. The VSEPR (Valence Shell Electron Pair Repulsion) Theory
  2. Valence Bond Theory
  • Orbital Overlap Concept
  • Directional Properties Of Bonds
  • Overlapping of Atomic Orbitals
  • Types of Overlapping and Nature of Covalent Bonds
  • The Strength of Sigma and Pi Bonds
  1. Hybridisation
  • Types of Hybridisation
  • Other Examples of Sp3, Sp2, and Sp Hybridisation
  • The Hybridisation of Elements Involving d Orbitals
  1. Molecular Orbital Theory
  • Formation of Molecular Orbitals, Linear Combination of Atomic Orbitals (LCAO)
  • Conditions For The Combination of Atomic Orbitals
  • Types of Molecular Orbitals
  • Energy Level Diagram For Molecular Orbitals
  • Electronic Configuration and Molecular Behaviour
  1. Bonding in Some Homonuclear Diatomic Molecules
  2. Hydrogen Bonding
  • Cause of Formation of Hydrogen Bond
  • Types of H-bonds.

When two atomic orbitals are mixed, it leads to the rise of new orbitals. The new orbitals are called Hybrid Orbitals. This process of intermixing atomic orbitals is called Hybridization. The intermixing leads to the formation of hybrid orbitals having completely different shapes, energies, etc. 

Types of Hybridization:

  • sp Hybridisation
  • sp2 Hybridisation
  • sp3 Hybridisation
  • sp3d Hybridisation
  • sp3d2 Hybridisation

In order to predict the shapes of covalent molecules, the VSEPR Theory (Valence Shell Electron Pair Repulsion Theory) provides a simple procedure. This theory was proposed by Sidgwick and Powell in 1940. The electron pairs’ repulsive interactions in the valence shell of the atoms were the basis for this theory. Nyholm and Gillespie further developed and redefined this theory and it was stated that a molecule’s shape depends on the valence shell electron pairs around the central atom. 

Solving these questions will assure that students score well in your exams. For help, students must refer to Chemistry Class 11 Chapter 4 NCERT Solutions that have answers to all the questions that are discussed in the NCERT textbook for Class 11 Chemistry.

Students can refer to the study material and solutions by Extramarks to understand the chapter of Chemical Bonding and Molecular Structure. Reading the chapters a couple of times and solving the questions using NCERT Solutions, will further strengthen the concepts of students.

The overlapping of atomic orbitals leads to the formation of any covalent bond in nature. The overlapping of 1s-orbitals of two hydrogen atoms forms the molecule of hydrogen. The geometry of molecules is also crucial in the case of polyatomic molecules. A part is played by the VSEPR theory in dictating the molecule’s geometry, however, the valence bond theory is more suited to provide an explanation for the directional properties of a bond.