Lakhmir Singh Chemistry Class 9 Solutions Atoms and Molecules (Chapter 3)

Lakhmir Singh Chemistry Class 9 Solutions ‘Atoms and Molecules’ – Chapter 3 will help you learn all the topics related to atoms and molecules that are discussed in the chapter. Till now, you already know what matter is. The chapter 3 of Lakhmir Singh Solutions will help you understand more about the particles from which matter is made of. We have prepared explanatory solutions for all the questions of the chapter so that you are left with no doubts.

Class 9 Chemistry Chapter 3 of Lakhmir Singh book has around 12 exercises with more than 150 questions. These questions will make your concept more clear of the chapter. The chapter covers different topics like laws of chemical combination, the law of conservation of mass, the law of constant proportions, atom and its size, symbols of the atom, atomic mass, the existence of the atom, molecule, molecules of elements and compounds, ions, writing chemical formulae, molecular mass, mole concept, etc. 

If you have doubts in any of these topics, just refer to our solutions of chapter 3 of class 9 chemistry book by Lakhmir Singh. We have provided clear explanations. Our solutions are based on the CBSE exam pattern only. All the important terms are explained with the help of diagrams and examples to make learning easier for you.

Important Topics for Lakhmir Singh Chemistry Class 9 Solutions ‘Atoms and Molecules’ – Chapter 3


The chapter begins with an introduction about Atoms. You will learn everything about atoms such as its size, characteristics, etc. Atom is basically the smallest particle of matter which cannot be divided further. You will also know about the modern-day symbols of atoms and their existence. 

Law of Conservation of Mass

As per this law, there is a change in mass when any chemical change takes place. The law of conservation states that mass can neither be created nor it can be destroyed. 


A molecule is known as a group of two or more atoms that are bonded together chemically. Also, the molecule is the smallest particle of an element or compound that can exist independently. Under this topic, you will learn about the molecules of elements, molecules of compounds, ions, writing chemical formulae, etc.

Exercise-Wise Discussion on Lakhmir Singh and Manjit Kaur Solutions for Class 9 Chapter 3

Exercise 1 (Page 129)

This set of exercises has 31 questions which are one-word answer questions. You should have knowledge of all the basics of the chapter like what is the law of conservation of mass, what is the mass and chemical formulae, etc. 

Exercise 2 (Page 130)

This set of exercises has 22 questions based on defining different topics, laws, calculating masses, identifying the molecules or atoms, etc. 

Exercise 3 (Page 131)

This exercise consists of only three numerical questions which are based on the laws. 

Exercise 4 (Page 132)

This exercise has 3 questions in which you need to find the solutions to the arisen situations like you will have to find mass, identifying the liquid or gas as if it is an element of the compound, proving the law, etc. 

Exercise 5 (Page 150)

This exercise has only two questions in which you have to find the number of electrons or defining the formula mass of a compound. 

Exercise 6 (Page 151)

The sixth exercise of the chapter has a total 21 questions based on finding the chemical formulae, naming the liquid or gases with their chemical formula etc. 

Exercise 7 (Page 152)

This exercise has only four questions which are numerical-based with some basic identification of the substances mentioned in the question. 

Exercise 8 (Page 153)

This exercise set has five questions in which you have to find the valencies and the formulae of different compounds. 

Exercise 9 (Page 172)

The exercise nine has 20 questions which are a combination of one-word answers to numerical-based questions. Thus, from this exercise set, you will have to answer different questions in one situation like finding the formula first, then molecular mass and then maybe valencies.

Exercise 10 (Page 173)

This exercise set has a total of 13 numerical questions based on molecular mass, the number of moles, etc. 

Exercise 11 (Page 174)

This exercise has a total of 8 questions which are all numerical based on the topics of the entire chapter. You need to find the mass of molecules or compounds, etc. 

Exercise 10, 11 and 12 have a mixture of questions which might be difficult for you at some point. To get the right solutions and to make the course content easy for you, you can refer to Lakhmir Singh and Manjit Kaur Solutions for Class 9 Chemistry Chapter 3 by Instasolv. 

Benefits of Lakhmir Singh Chemistry Class 9 Solutions ‘Atoms and Molecules’ – Chapter 3

Are you one of those who are facing issues in finding the right solutions to all the questions of chapter 3? Do you want somebody to guide you properly? Then, Instasolv is the right study companion for you. The Instasolv team is proficient in CBSE Class 9 Chemistry syllabus and all of your doubts will say goodbye within minutes. The Lakhmir Singh Chemistry Class 9 Solutions for Chapter 3 are designed in a manner that the chapter will eventually be interesting for you. You will not face any sort of issues once you will read the solutions.