NCERT Solutions for Class 9 Science, Chapter 3 - Atoms and Molecules

In previous chapters, you studied that everything around us is made up of matter.
However, have you ever wondered what matter is made up of? Atoms! Yes, Atoms
are the fundamental building blocks of matter; atoms are the smallest particles of
any element and made up of protons, electrons and neutrons. When atoms group
together, they form a molecule. Thus, a molecule consists of atoms that are bonded
together; and when a molecule consists of different atoms, it becomes a compound.
Thus, whatever you see around you, everything is made up of atoms.

In NCERT Solutions for Class 9 Science, Chapter 3, you’ll get in-depth
knowledge about atoms, atomic mass, molecules, molecules of elements and
compounds, different chemical formulae and much more.

Let’s take a look at topics and sub-topics of Class 9 Science Chapter 3, Atoms and Molecules

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?
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?
3.3.1 Molecules of Elements
3.3.2 Molecules of Compounds
3.3.3 What is an Ion?
3.4 Writing Chemical Formulae
3.4.1 Formulae of Simple Compounds
3.5 Molecular Mass and Mole Concept
3.5.1 Molecular Mass
3.5.2 Formula Unit Mass
3.5.3 Mole Concept

In Class 9 Science Chapter 3, you will learn – 

Section 3.1 – In this section, you’ll study the laws of chemical combinations
such as the Law of Conservation of Mass and the Law of Constant Proportions as
proposed by Antoine L. Lavoisier along with other scientists. You’ll also come
across Dalton’s Atomic Theory.

Section 3.2 – In this section, you’ll learn what an atom is, modern-day symbols of
atoms of different elements, what is atomic mass, how big are atoms, symbols for
some elements, relative atomic mass of the atom of an element and more.

Section 3.3 – In this section, you’ll learn how to define a molecule, the molecules
of an element, molecules of a compound, atomicity of some non-metals, the
formation of molecules of compounds, what is an ion, and more.

Section 3.4 – In this section, you’ll acquire knowledge about what is valency,
names and symbols of some ions, rules that you need to follow while writing a
chemical formula, formulae of simple compounds, and more.

Section 3.5 – In this section, you’ll study what do you mean by molecular mass,
formula unit mass, the relationship between a mole, Avogadro number and mass.

In this chapter, you are provided with several diagrams, activities and examples
with their solutions for a clear understanding of Atoms and Molecules. To know
more about NCERT Solutions for Class 9 Chapter 3 you should explore the
exercises mentioned in this chapter. You can also download the Atoms and
Molecules Class 9 Solutions PDF, solved by our science experts.