Get Dream IIT in Drop Year | Up to 70% OFF | Limited Seats

NCERT Solutions Class 9 Science - Chapter 3 Atoms and Molecules - PDF Download

JEE Mains & Advanced

NCERT solutions for class 9 science Chapter 3 – Atoms and Molecules is a comprehensive study material that is prepared by experts and provides answers to all the questions in the exercise of the chapter. NCERT solutions are very useful for understanding concepts and self analysis.

The solutions cover all the topics and are presented in an easy-to-understand manner. Students should try to solve the questions after they have completed the complete syllabus and overcome their shortcomings before the upcoming exams. This will help them to score higher in the examination.

For those students who are having difficulty with the NCERT issues in the Class 9 Atoms & Molecules chapter, the eSaral experts have prepared the NCERT Solutions for the chapter. The PDF file for the chapter is now available for free downloading. The experts have taken a straightforward approach in preparing the solutions for the chapter, which will enable students to solve and practice all exercise questions accurately. Therefore, students can download the PDF file and refer the solutions for effective examination preparation. For those seeking better solutions in the Maths chapter, the NCERT Solutions for the chapter can be downloaded. These solutions will enable students to revise the syllabus and score higher marks in their examinations.

NCERT Solutions for Class 9 Science Chapter 3 Topics

Section Name

Topic Name


Atoms and Molecules


Laws of Chemical Combination


What is an Atom?


What is a Molecule?


Writing Chemical Formulae


Molecular Mass

3.1 Laws of Chemical Combination: The Laws of Chemical Combination are the general principles that govern how elements and compounds behave in chemical reactions. These general principles serve as the basis for understanding how elements and compounds combine to form compounds, and how reactants convert into products in chemical reactions.

Subtopics covered in the section 3.1 Laws of Chemical Combination:

      3.1.1 Law of conservation of mass

      3.1.2 Law of constant proportions

3.2 What is an Atom?: An atom is one of the smallest particles in the universe. It's the smallest part of any element that still has the same chemical properties as the element it's made up of. atoms are super tiny and made up of tiny subatomic particles like protons, electrons, and neutrons.

Subtopics covered in the section 3.2 What is an Atom?:

      3.2.1 What are the modern day symbols of atoms of different elements?

      3.2.2 Atomic mass

      3.2.3 How Do Atoms Exist?

3.3 What is a Molecule?: A molecule is generally defined as a collection of two or more atoms that are chemically bound together, i.e., held together by attraction. A molecule can also be defined as the smallest particle of any element or a compound that is able to exist independently and displays all of the properties of that element.

Subtopics covered in the section 3.3 What is a Molecule?:

     3.3.1 molecules of elements

     3.3.2 molecules of compounds

     3.3.3 what is an ion?

3.4 Writing Chemical Formulae: Chemical formula writing is a method of describing the composition of a chemical compound by using symbols for elements and numerical numerals to indicate the number of atoms present in the compound.

Subtopics covered in the section 3.4 Writing Chemical Formulae:

     3.4.1 Formulae of Simple Compounds

3.5 Molecular Mass: Molecular mass is the mass of all the atoms that make up a molecule. It's usually expressed in units like amu or g/mol. It's a big part of chemistry and can be used to figure out things like how many moles a molecule has or how much weight a substance has.

Subtopics covered in the section 3.5 Molecular Mass:

    3.5.1 Molecular Mass

    3.5.2 Formula Unit Mass

Key Features of Class 9 Science Chapter 3

  • When a chemical reaction occurs, the mass of the reactants and products does not change. This is called the law of conservation of mass.

  • A pure chemical compound always contains elements in a certain proportion by mass, this is called the Law of Definite proportion.

  • Atoms are the smallest particles of an element that cannot usually exist independently and maintain all its chemical properties.

  • Molecular compounds are characterized by their chemical formula, which is determined by the valence of each element in a compound.

  • In an ionic compound, the charge of each ion determines the chemical formula.

  • A molecule is a small part of an element, or a compound, that can exist independently under normal conditions. It displays all properties of a substance.

  • A chemical formula shows the component elements of a compound, as well as the number of elements of each combining element.

  • Polyatomic particles are clusters of atoms, each of which carries a fixed charge.

Benefits of Downloading the PDF of NCERT Solutions Class 9 Science Chapter 3 Atoms and Molecules 

Downloading the pdf of NCERT solutions for Class 9 Science chapter 3 “Atoms and molecules” can help students in several ways, such as:

Easy access: The PDF is easily accessible on your device, so you can easily access the solutions anytime, even if you don’t have an internet connection

Comprehensive understanding: The solutions provide detailed explanations for every question and concept of the chapter, helping students understand the subject matter better

Organized learning: The solutions are arranged in a systematic way, following the order of the textbook, making it easy for students to follow the chapter’s flow

Clear explanations: The solutions provide clear and concise explanations for complex concepts, making it easier to understand them

Problem solving abilities: The solutions provide a variety of problems and exercises that students can use to practice and develop problem-solving abilities.

Self-assessment: Students can use the solutions after trying questions on their own to evaluate their performance and find areas of improvement.

Aligned with the examination pattern: The solutions are designed to match the examination pattern, helping students prepare well for exams.

Frequently Asked Questions

Question 1: What is an atom?

Answer 1: The atom is the smallest, indivisible part of an element that maintains its chemical properties. The atom is made up of a nucleus with protons and electrons surrounding it in terms of energy.

Question 2: What is a chemical formula?

Answer 2: A chemical formula is a way of representing the type and number of atoms in a compound. It's made up of symbols and numbers that represent the number of atoms in the compound.


Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now