CBSE Class 9 Science Structure of The Atom Worksheet Set D

Access the latest CBSE Class 9 Science Structure of The Atom Worksheet Set D. We have provided free printable Class 9 Science worksheets in PDF format, specifically designed for Chapter 4 Structure of the Atom. These practice sets are prepared by expert teachers following the 2025-26 syllabus and exam patterns issued by CBSE, NCERT, and KVS.

Chapter 4 Structure of the Atom Science Practice Worksheet for Class 9

Students should use these Class 9 Science chapter-wise worksheets for daily practice to improve their conceptual understanding. This detailed test papers include important questions and solutions for Chapter 4 Structure of the Atom, to help you prepare for school tests and final examination. Regular practice of these Class 9 Science questions will help improve your problem-solving speed and exam accuracy for the 2026 session.

Download Class 9 Science Chapter 4 Structure of the Atom Worksheet PDF

SENIOR SECTION

DEPARTMENT OF CHEMISTRY

CLASS IX

STRUCTURE OF ATOM

WORKSHEET- IV
 
1 Mark Questions:
 
1i.. On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole?
 
ii. Where are electrons found in the atom?
 
iii. What are canal rays?
 
iv. Why is the nucleus of an atom positively charged?
 
v. Why did Rutherford select a gold foil in his α-ray scattering experiment?
 
vi. If Mg2+ has 12 protons and 12 neutrons, what is its atomic number and mass number?
 
vii. What is the defect of Rutherford's atom model?
 
viii. Define valency & give one example of a monovalent element.
 
ix. An atom of an element has 7 electrons in its L-shell, name the element and write it's atomic number?
 
x. Why Mg atom gets 2+ charge when it loses two electrons ?
 
xi. Name the particles which determine the mass of an atom.
 
xii. Which of the following are isotopes and which are isobars? Argon, Protium, Calcium, Deuterium
 
2 Marks Questions:
 
2i.. a) Calculate the average atomic mass of chlorine if it exists in two isotopes 35Cl ( 75%) and 37Cl (25%).
 
b) Write the main drawback of Rutherford model of the atom.
 
ii. What are alpha particles? How are they related to Helium gas?
 
iii. State the characteristics of nucleus of an atom.
 
iv. Describe Bohr’s model of the atom?
 
v. The atomic number of chlorine is 17 and mass number is 35.
 
a. What would be the electronic configuration of a negatively charged chloride ion, Cl- ?
 
b. What would be the atomic number and mass number of Cl- ?
 
vi. What is electronic configuration and how is the valency of an atom related to it ?
 
vii. Which of the two would be chemically more reactive element, X of atomic number 18 or Y of atomic number 17 &why?
 
viii. What are isotopes? Why do isotopes show similar chemical properties but they differ in physical properties?
 
ix. Write isotopes of uranium and its uses.
 
x. Write one pair of Isobars. Why the chemical properties of isobars are not similar?
 
3 Marks Questions:
 
3i.. Explain Rutherford's gold foil experiment with diagram.
 
 ii. Write two points of difference between isotopes and isobars.
 
iii. The average atomic mass of a sample of an element ‘X’ is 16.2u. What is the percentage of each isotope 16X and 18X in the sample?
 
iv. Define valency of an element. Find the valency of chlorine and magnesium.
 
v. What is the similarity in the electronic structure of the following set of atoms?
 
Lithium, Sodium & Potassium.Which of the above element is most reactive and why?
 
vi. Complete the following table. Element At. No. Mass

CBSE Class 9 Science Structure of The Atom Worksheet Set D 1



vii. Give reason for the following
 
a) An atom is electrically neutral
 
b) Noble gases show least reactivity
 
c) Nucleus of an atom is heavy and positively charged.
 
d) Ions are more stable than atoms.
 
viii. An element has an atomic number 12 and mass number 26.Draw a diagram showing thedistribution of electrons in the orbits and the nuclear composition of the neutral atom. If thiselement X combines with another element Y whose electronic configuration is 2,8,7, what will be the formula of the compound thus formed?
 
ix. Name the Scientists who have contributed the following towards the understanding of the atomic structure.
 
a) Discovery of electrons
 
b) Canal rays
 
c) Concept of nucleus
 
d) Stationary orbits
 
e) Indivisibility of atoms
 
f) Neutron
 
x. Write the distribution of electrons in an atom of an element whose atomic number is
 
18.What is special about the outermost shell of an atom in this element?
 
xi. State the observations in alpha particle scattering experiment which led to Rutherford making the following conclusions.
 
a) Most of the space in atom is empty.
 
b) Whole mass of atom is concentrated in its centre.
 
c) Centre is positively charged.
 
xii. Explain with examples :
 
a) Atomic number
 
b) Mass Number
 
c) Isotopes
 
d) Isobars
 
xiii. Give any two uses of isotopes.
 
xiv. Define Electronic configuration.
 
xv. Compare the properties of electrons ,protons and neutrons.
 
Multiple choice questions: 
 
i)An ion of an element has three positive charges. The mass number of atom of the element is 27 and the number of neutrons in the atom is 14. The number of electrons in the ion is:
 
a) 13 b) 10 c)14 d)16
 
ii) Isotopes of an element contain:
 
a) Same number of neutrons but different number of protons.
 
b) Same number of neutrons but different number of electrons.
 
c) Different number of protons as well as different number of neutrons.
 
d) Different number of neutrons but same number of protons.
 
iii) The atomic numbers of four elements A , B , C and D are 12, 13 , 15 & 3 respectively.
 
The element which cannot form a cation is :
 
a) A       b) B           c) C           d) D
 
iv) Which of the following is the correct electronic distribution of magnesium ion?
 
a) 2,8       b)2,8,4        c)2,8, 8           d) 2 , 8 , 7
 
Assertion-Reason questions :  
 
The questions below consist of statement of an assertion and a reason. Choose the correct option.
 
(a) If both Assertion and Reason are true and Reason is the correct explanation ofnAssertion.
 
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
 
c) If Assertion is correct but Reason is incorrect
 
d) If Assertion is incorrect , but reason is correct
 
i) Assertion: 35Cl17 and 37Cl17 are called isotopes of chlorine.
 
Reason: Isotopes of an element have same mass number but different atomic numbers.
 
ii) Assertion: Neon is considered as an inert element.
 
Reason: It has a stable electronic configuration of 2,8.
 
iii) Assertion: Nucleus of an atom is positively charged.
 
Reason: Nucleus is the central part of the atom at which almost the entire mass is concentrated.


Please click on below link to download CBSE Class 9 Science Structure of The Atom Worksheet Set D

Chapter 01 Matter in Our Surroundings
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set A
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set B
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set C
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set D
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set E
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set F
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set G
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set H
CBSE Class 9 Science Matter in Our Surroundings Worksheet Set I
Chapter 02 Is Matter Around Us Pure
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set A
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set B
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set C
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set C
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set D
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set D
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set E
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set E
CBSE Class 9 Science Is Matter Around Us Pure Worksheet Set F
Chapter 03 Atoms and Molecules
CBSE Class 9 Science Atoms and Molecules Worksheet Set A
CBSE Class 9 Science Atoms and Molecules Worksheet Set B
CBSE Class 9 Science Atoms and Molecules Worksheet Set C
CBSE Class 9 Science Atoms and Molecules Worksheet Set D
CBSE Class 9 Science Atoms and Molecules Worksheet Set E
CBSE Class 9 Science Atoms and Molecules Worksheet Set F
CBSE Class 9 Science Atoms and Molecules Worksheet Set G
CBSE Class 9 Science Atoms and Molecules Worksheet Set H
Chapter 04 Structure of the Atom
CBSE Class 9 Science Structure of The Atom Worksheet Set A
CBSE Class 9 Science Structure of The Atom Worksheet Set B
CBSE Class 9 Science Structure of The Atom Worksheet Set C
CBSE Class 9 Science Structure of The Atom Worksheet Set D
Chapter 05 The Fundamental Unit of Life
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set A
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set B
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set C
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set D
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set E
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set F
CBSE Class 9 Science Fundamental Unit of Life Worksheet Set G
Chapter 06 Tissues
CBSE Class 9 Science Plant Tissues Worksheet Set A
CBSE Class 9 Science Tissue Worksheet Set C
CBSE Class 9 Science Tissue Worksheet Set D
CBSE Class 9 Science Tissue Worksheet Set E
CBSE Class 9 Science Tissue Worksheet Set F
CBSE Class 9 Science Tissues Worksheet Set A
CBSE Class 9 Science Tissues Worksheet Set B
Chapter 07 Motion
CBSE Class 9 Science Motion Worksheet Set A
CBSE Class 9 Science Motion Worksheet Set B
CBSE Class 9 Science Motion Worksheet Set C
CBSE Class 9 Science Motion Worksheet Set D
CBSE Class 9 Science Motion Worksheet Set E
CBSE Class 9 Science Motion Worksheet Set F
CBSE Class 9 Science Motion Worksheet Set G
CBSE Class 9 Science Motion Worksheet Set H
CBSE Class 9 Science Motion Worksheet Set I
CBSE Class 9 Science Motion Worksheet Set J
Chapter 08 Force and Laws of Motion
CBSE Class 9 Science Force and Laws of Motion Worksheet Set A
CBSE Class 9 Science Force and Laws of Motion Worksheet Set B
CBSE Class 9 Science Force and Laws of Motion Worksheet Set C
CBSE Class 9 Science Force and Laws of Motion Worksheet Set D
CBSE Class 9 Science Force and Laws of Motion Worksheet Set E
CBSE Class 9 Science Force and Laws of Motion Worksheet Set F
Chapter 09 Gravitation
CBSE Class 9 Science Gravitation Worksheet Set A
CBSE Class 9 Science Gravitation Worksheet Set B
CBSE Class 9 Science Gravitation Worksheet Set C
CBSE Class 9 Science Gravitation Worksheet Set D
Chapter 10 Work and Energy
CBSE Class 9 Science Work and Energy Worksheet Set A
CBSE Class 9 Science Work and Energy Worksheet Set B
Chapter 11 Sound
CBSE Class 9 Science Sound Worksheet Set A
CBSE Class 9 Science Sound Worksheet Set B
Chapter 12 Improvement in Food Resources
CBSE Class 9 Science Improvent in Food Resources Worksheet Set A
CBSE Class 9 Science Improvent in Food Resources Worksheet Set B
Chapter 13 Why Do We Fall Ill
CBSE Class 9 Science Why Do We Fall ill Worksheet Set A
CBSE Class 9 Science Why Do We Fall ill Worksheet Set B
Chapter 14 Natural Resources
CBSE Class 9 Science Natural Resource Worksheet Set C
CBSE Class 9 Science Natural Resource Worksheet Set D
CBSE Class 9 Science Natural Resource Worksheet Set E
CBSE Class 9 Science Natural Resource Worksheet Set F
CBSE Class 9 Science Natural Resources Worksheet Set A
CBSE Class 9 Science Natural Resources Worksheet Set B
z More Worksheets for Class 9 Science
CBSE Class 9 Science Lab Worksheet Different Chemical Changes
CBSE Class 9 Science Lab Worksheet law of Conservation of Mass
CBSE Class 9 Science Lab Worksheet Melting Point of Ice
CBSE Class 9 Science Lab Worksheet Preparation of Mixture and Compound
CBSE Class 9 Science Lab Worksheet Separation of Different Components
CBSE Class 9 Science Lab Worksheet True Solution Colloid Suspension
CBSE Class 9 Science Worksheet Set A
CBSE Class 9 Science Worksheet Set B
CBSE Class 9 Science Worksheet Set C
CBSE Class 9 Science Worksheet Set D
CBSE Class 9 Science Worksheet Set E
CBSE Class 9 Science Worksheet Set F
CBSE Class 9 Science Worksheet Set G
CBSE Class 9 Science Worksheet Set H
CBSE Class 9 Science Worksheet Set I
CBSE Class 9 Science Worksheet Set J
CBSE Class 9 Science Worksheet Set K
CBSE Class 9 Science Worksheet Set L
CBSE Class 9 Science Worksheet Set M Solved
CBSE Class 9 Science Worksheet Set N Solved
CBSE Class 9 Science Worksheet Set O Solved
CBSE Class 9 Science Worksheet Set P Solved
CBSE Class 9 Science Worksheet Set Q Solved
CBSE Class 9 Science Worksheet Set R Solved
CBSE Class 9 Science Worksheet Set S Solved
CBSE Class 9 Science Worksheet Set T Solved
~ Class 9 Science (Old Chapters)
CBSE Class 9 Science Diversity in Living Organism Worksheet Set A
CBSE Class 9 Science Diversity in Living Organism Worksheet Set B
CBSE Class 9 Science Diversity In Living Organisms Worksheet Set C
CBSE Class 9 Science Diversity In Living Organisms Worksheet Set D
CBSE Class 9 Science Diversity In Living Organisms Worksheet Set E
CBSE Class 9 Science Diversity In Living Organisms Worksheet Set F

Important Practice Resources for Class 9 Science

Chapter 4 Structure of the Atom CBSE Class 9 Science Worksheet

Students can use the Chapter 4 Structure of the Atom practice sheet provided above to prepare for their upcoming school tests. This solved questions and answers follow the latest CBSE syllabus for Class 9 Science. You can easily download the PDF format and solve these questions every day to improve your marks. Our expert teachers have made these from the most important topics that are always asked in your exams to help you get more marks in exams.

NCERT Based Questions and Solutions for Chapter 4 Structure of the Atom

Our expert team has used the official NCERT book for Class 9 Science to create this practice material for students. After solving the questions our teachers have also suggested to study the NCERT solutions  which will help you to understand the best way to solve problems in Science. You can get all this study material for free on studiestoday.com.

Extra Practice for Science

To get the best results in Class 9, students should try the Science MCQ Test for this chapter. We have also provided printable assignments for Class 9 Science on our website. Regular practice will help you feel more confident and get higher marks in CBSE examinations.

Where can I download latest CBSE Practice worksheets for Class 9 Science Chapter 4 Structure of the Atom

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