CBSE Class 9 Science Atoms and Molecules Worksheet Set H

Access the latest CBSE Class 9 Science Atoms and Molecules Worksheet Set H. We have provided free printable Class 9 Science worksheets in PDF format, specifically designed for Chapter 3 Atoms and Molecules. These practice sets are prepared by expert teachers following the 2025-26 syllabus and exam patterns issued by CBSE, NCERT, and KVS.

Chapter 3 Atoms and Molecules 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 3 Atoms and Molecules, 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 3 Atoms and Molecules Worksheet PDF

 
ATOMS AND MOLECULES

1 Mark Questions:
 
i. State the law of constant proportion.
 
ii. Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass?
 
iii. Write the molecular formula of a diatomic gas and a triatomic gas.
 
iv. Name the term used for the symbolic representation of a molecule of an element or a compound? Give an example of it.
 
v. In the reaction between copper sulphate solution and sodium sulphide solution, 15.9g copper sulphate completely reacts with 7.8g of sodium sulphide. It is observed that 9.5g of copper sulphide is formed. What is the mass of sodium sulphate solution formed?
 
vi. Why is the symbol of gold taken as Au?
 
vii. Calculate the formula unit mass of NaHCO3. (at.mass: Na=23u H=1u C=12u,O=16u)
 
viii. Define Avogadro’s number. What is its value?
 
ix. What is the ratio between masses of carbon and oxygen in CO2?
 
x. Define atomicity of an element.
 
xi. Nitrogen and hydrogen are present in ammonia in the ratio 14:3 by mass.What would be the mass of nitrogen if the actual mass of hydrogen is 9g?
 
2 Mark Questions:
 
i. Silver nitrate solution was mixed with 5g of sodium chloride solution to verify law of conservation of mass. 8.1 gram of silver chloride was formed and sodium nitrate formed was equal to half of the amount of silver nitrate solution used. What is the amount of silver nitrate used and sodium nitrate formed?
 
ii. (a)What is the significance of symbols?
 
(b)What do the abbreviations 2O and O2 stand for?
 
iii. (a)Taking the example of water, explain the law of constant proportion.
 
(b)Which postulate of Daltons’ atomic theory explains this law?
 
iv. What are polyatomic ions? Give any two examples.
 
v. Give the names of elements present in:-
 
(a)sodium nitrate (b) ammonium hydrogen carbonate (c) iron(III)sulphate
 
vi. Write the formulae and names of compounds formed by combination of:
 
(a) Fe3+ and SO42- (b) NH4+ and CO32-
 
vii. Using the valencies, write down the chemical formulae of the following compounds:
 
(a)calcium nitrate                            (b) manganese(IV) oxide
 
(c) ammonium phosphate                (d) aluminium chloride
 
 
viii. Define following :- (a)formula unit mass (b) molecular mass
 
ix. Define mole and find the number of moles present in 1.6g of oxygen gas.
 
x. (a)How many grams of chlorine are contained in one mole of chlorine?
 
(b) How many molecules are there in 7.1g of chlorine gas?
     (atomic mass: Cl=35.5u)
 
xi. Write the valency of each cation and anion in the following compounds.
 
(a) FeN ( b) CuSO4
 
(c) AlPO4 (d) NH4HCO3

3 Mark Questions:
 
i. (a) What are ionic and molecular compounds? Give examples.
 
(b) Find the ratio by mass of the combining elements in the following compounds.
 
(a) SO2 (b) CaH2 ( at.mass: S=32u , O=16 , Ca=40u , H=1u )
 
ii. Calculate the mass of 0.5 mole of sugar (C12H22O11).
 
(at.mass: C=12u, H=1u, O=16u).
 
iii. Name the ionic compound that is obtained from sea water and calculate the number of moles present in 5.85 g of this compound.
 
iv. What is the atomicity of sulphur. Calculate the number of moles in 0.4g of sulphur powder. ( at.mass of S= 32 )
 
v. Calculate the number of moles:
 
(a) 3.011 x 1023 atoms of carbon (b) 9g of water
 
( at. mass: O = 16 u, H=1u C = 12u )
 
vi. (a) Which has more number of particles , 48g of Mg or 7g of nitrogen?
 
(at.mass: Mg = 24 u, N = 14 u)
 
(b) State the postulates of Dalton’s atomic theory.
 
vii. Calculate the number of atoms in 120g of calcium and 120g of iron. Which one has more number of atoms? (at.mass: Ca = 40 u , Fe= 56 u)
 
viii. (a) Calculate the number of molecules in 90g of C6H12O6.
 
( at.mass: C=12u H=1u O=16u)
 
(b) Calculate the mass of 0.5 moles of nitrogen gas. (at.mass N=14u)
 
ix. Name and state the laws of chemical combination.
 
x. An element P shows two valencies 3 and 4 .Write the formulae of possible oxides of this element.
 
xi. Calculate the molecular mass / formula mass of each of the following and write the corresponding value of gram molecular mass.
 
(a) ethanoic acid (CH3COOH) (b) sugar (C12H22O11)
 
(c)sodium carbonate (Na2CO3) (d) copper sulphate (CuSO4.5H2O)
 
(at.mass: H=1u O=16u C=12u Na=23u S=32u Cu=63.5u )
 
xii. Define the following terms :
 
a) atom    b) molecule     c) polyatomic molecule    d) unified mass
 
e) relative atomic mass    f) molecular formula       g) molar mass
 
Multiple choice questions :
 
i) The symbols of the elements cobalt , zinc , manganese and fluorine written by a student are as follows. Which symbol is the correct one?
 
a) CO             b) ZN          c) Mg                 d)F
 
ii)The number of electrons in an ion X3- is 10. The atomic number of X is :
 
a)7               b)5              c)10                  d)8
 
iii)If 12g of carbon has n atoms , then what is the number of atoms in the same amount of Mg? (Given that atomic mass of C=12u & Mg=24u)
 
a)n               b) 2n           c) n/2               d)1.5n
 
iv) Which of the following represents the correct chemical formula?
 
a)NaO          b)Na3N       c)NaSO4            d)NaS
 
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 of Assertion.
 
(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: One mole of hydrogen atom is equal to half mole of hydrogen molecule.
 
Reason: Every molecule of hydrogen is constituted by two atoms.
 
ii)Assertion: Atoms are electrically neutral.
 
Reason: Atoms contain equal number of electrons and protons which are oppositely charged.
 
iii)Assertion: A positively charged atom is called a cation.
 
Reason: A cation is formed when an atom gains one or more protons.
 
 
 
 
Please click on below link to download CBSE Class 9 Science Atoms and Molecules Worksheet Set H
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 3 Atoms and Molecules CBSE Class 9 Science Worksheet

Students can use the Chapter 3 Atoms and Molecules 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 3 Atoms and Molecules

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.

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