NCERT Exemplar Class 9 Science Chapter 4 Solutions: Structure of The Atom

NCERT Exemplar Class 9 Science Solutions for Chapter 4 are going to discuss the structure of an atom. You have studied different properties and the existence of atoms in the previous chapter of NCERT Exemplar Class 9 Science. But it is essential to understand the structure in detail to know how it performs this way.

This chapter is going to cover different topics like-charged particles of matter, different models explaining the structure of an atom, Thomson’s model of an atom, Rutherford’s model of an atom, neutrons, atomic and mass number, etc. It covers different exercises like multiple-choice questions to long answer questions. There are 49 exemplar problems in this chapter.

The questions are designed in a manner that you can easily prepare for your CBSE as well as other competitive exams. To score good marks, you need to thoroughly understand the chapter. The solutions to all the NCERT Exemplar Class 9 Science Chapter 4 Problems are available to you at the website of Instasolv. Not only you get the best solutions but with us, you can find the important topics of the chapter here. We promise you the best guidance.

Important Topics for NCERT Exemplar Class 9 Science Solutions Chapter 4: Structure of Atom

This chapter of chemistry deals with different topics that will explain the structure of an atom. Explaining the structure of the atom was a challenge for all scientists.

Charged Particles of Matter

The topic is going to teach you about how the matter contains charged particles. While rubbing any 2 objects together, they get electrically charged. The main question is, from where does this charge come from. This topic will tell you that an atom is indivisible and it consists of charged particles.

Structure of an Atom

In order to understand the structure of atoms, different models are proposed that explain the structure of the atom in different ways.

Thomson’s Model of an Atom

This model is going to tell that a positively charged sphere consists of electrons that are divided like currents in a Christmas pudding. The model proposed that atoms:

  • Atoms consist of a positively charged spare that carries electrons. 
  • The positive and negative charges are equal in magnitude.

Rutherford’s Models of an Atom

In this model, you will know how Rutherford explained the structure of atoms. He concluded that:

  • An atom consists of positively charged centres that are’ known as the nucleus. The mass of an atom resides in the nucleus. 
  • The electron revolves in well-defined orbits around the nucleus.
  • The size of the nucleus is quite smaller than the atom.

Bohr’s Model of an Atom

This model explained that:

  • Some special orbits are known as discrete orbits of electrons.
  • While the electrons revolve in the discrete orbit, they do not radiate energy.


Neutrons are the subatomic particles that consist of no charge and possess mass equal to that of a proton.

How are the Electrons Distributed in Different Shells?

This topic explains in which orbit and how the electrons are more. Also, this topic will tell you about valence electrons. Also, you will know how much valence electrons are and how they divide in a particular shell.

Atomic Number and Mass number

In this topic, you will know about the total number of protons that are present in the nucleus of an atom. Also, you will know about mass numbers the other topics covered are isotopes and isobars.

Exercise Discussion of NCERT Exemplar Class 9 Science Solutions Chapter 4: Structure of Atom

  • With a total of 49 questions, the exercises consist of three types of sets that are discussed below. 
  • The first set of exercises starts with 18 multiple-choice questions. You need to choose the correct option on what a model proposed, representation of an element, etc. 
  • The second set consists of short answer questions which are a combination of fill in the blank type questions, matching the name of scientists with their findings, the one-line answer questions, etc. The different topics covered are finding the valence of the atom, finding the electron distribution of atoms or giving justification to any scientist’s model.
  • The third set of exercise has long-answer questions in which you will have to either explain the findings or drawbacks of a model, finding the atomic or mass number, etc.

Benefits of NCERT Exemplar Class 9 Science Solutions Chapter 4 By Instasolv

Studying for Chemistry exams is a task for everybody. Preparing for the exams in the right manner is not easy for everybody and that is why Instasolv is here to provide you with the best guidance on NCERT Exemplar Class 9 Science Chapter 4.

Teaching has been inflow from the last decades in different forms but today, Instasolv makes use of the technology and the best experts to provide you with the best teaching. We have designed easy to understand and stepwise solutions to NCERT Exemplar exercises for you so that you can study from your most comfortable space.