NCERT Class 9 Science Chapter 3 Atoms and Molecules MCQ

NCERT MCQ Solutions for Class 9 Science Chapter 3 Atoms and Molecules provide a group of multiple-choice questions covering atomic structure, molecular composition, the mole concept and chemical laws. These NCERT MCQ solutions help students grasp key concepts like Dalton’s Atomic Theory, the law of conservation of mass and atomic mass calculations. Practicing these MCQs enhances problem-solving skills, making exam preparation effective. These solutions are essential for understanding fundamental chemistry principles in Class 9.
Class 9 Science Chapter 3 NCERT Solutions
Class 9 Multiple Choice Questions
Class 9 Science MCQ

Basics to Atoms and Molecules in Class 9 Science MCQ

Atoms and molecules are fundamental building blocks of matter, forming the basis of chemistry and physics. In Class 9 Science Chapter 3 MCQ, students explore atomic structure, molecular composition and the laws governing chemical reactions. Atoms and Molecules NCERT Class 9 MCQ section helps students understand Dalton’s Atomic Theory, which states that all matter is composed of indivisible atoms. Class 9th Science Chapter 3 Multiple Choice Questions focus on atomic mass, the law of conservation of mass and Avogadro’s number. Understanding these concepts through Class 9 Science Chapter 3 Quiz enhances problem-solving skills and prepares students for competitive exams. CBSE Atoms and Molecules Class 9 Questions require a deep conceptual understanding of atomic properties and their interactions.

Q1. Molecular mass of glucose is

[A]. 45 u

[B]. 90 u

[C]. 180 u

[D]. 360 u

Q2. Atomic mass of chlorine is

[A]. 34.5 u

[B]. 35.5 u

[C]. 17.5 u

[D]. 17 u

Q3. The formula of calcium phosphate is

[A]. CaPO₄

[B]. (CaPO₄)₃

[C]. Ca₂PO₄

[D]. Ca₃(PO₄)₂

MCQs Based on the Law of Conservation of Mass

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One of the core principles in Class 9 Chemistry Chapter 3 MCQ is the law of conservation of mass, which states that mass remains constant in a chemical reaction. This principle is frequently tested in Atoms and Molecules MCQ Questions, requiring students to balance chemical equations and understand reactant-product mass relationships. NCERT Best Solutions Class 9 Science Chapter 3 Practice Questions challenge students to determine how reactants transform into products without any loss or gain of mass. In various Atoms and Molecules Class 9 Quiz sessions, students calculate reactant-product mass ratios in chemical reactions. These concepts are further reinforced through Class 9 Science Chapter 3 Test, where numerical problems based on this law are frequently included.

Q4. The law of constant proportion states

[A]. Matter can neither be created nor destroyed

[B]. Volume of a gas varies inversely as its pressure at constant temperature

[C]. Elements are always present in a fixed proportion by mass in a chemical compound

[D]. None of the above

Q5. Mass can neither be created nor destroyed in a chemical reaction. This is the statement of a law called

[A]. Law of constant proportion

[B]. Law of conservation of mass

[C]. Periodic law

[D]. None of these

Q6. Magnesium and sulphur combine to form magnesium sulphide with the masses of magnesium and sulphur in the ratio of

[A]. 4:3

[B]. 2:3

[C]. 3:2

[D]. 3:4

Molecular Mass and Mole Concept in Class 9th Chemistry MCQ

The Atoms and Molecules Class 9 Practice Questions often test students on the concept of molecular mass and the mole, which are very useful for understanding chemical reactions quantitatively. NCERT Class 9 Science Chapter 3 Objective Questions include problems related to molar mass calculations, Avogadro’s constant and empirical formulae. Students must grasp how the mole concept helps in converting between the number of particles and grams of a substance. In Atoms and Molecules Class 9 Objective Questions, they apply stoichiometric principles to determine reactant-product relationships. CBSE Class 9th Science Chapter 3 Online Test typically covers numerical problems involving moles, molecular weight and percentage composition, making it essential to practice extensively.

Q7. Tick the correct statement

[A]. Atoms of the same element can join together to form molecules

[B]. Atoms of light and heavy elements can join together to form molecules

[C]. Atoms of different elements can join together to form molecules

[D]. Atoms of same or different elements can join together to form molecules

Q8. According to Greek philosophers, the smallest particle of matter that could not be further subdivided was called

[A]. Atom

[B]. Electron

[C]. Molecule

[D]. Ion

Q9. Valencies of aluminium and phosphate are

[A]. +2 and -3 respectively

[B]. + 2 and -2 respectively

[C]. + 3 and -2 respectively

[D]. + 3 and -3 respectively

Understanding Atomic Theories and Their Applications

Dalton’s Atomic Theory, Bohr’s model and the modern quantum mechanical model are integral to Atoms and Molecules Class 9 Test. In Class 9 Science Chapter 3 PDF, students find detailed explanations of atomic models and their experimental basis. Atoms and Molecules Class 9 PDF provides topic-wise clarity on subatomic particles like protons, neutrons and electrons. Class 9 Science Chapter 3 Notes elaborate on Rutherford’s Gold Foil Experiment, which led to the discovery of the atomic nucleus. Through Atoms and Molecules Class 9 Notes, students learn how atomic theories evolved based on experimental evidence and theoretical advancements.

Q10. The correct way of writing the symbol of aluminium is

[A]. al

[B]. Al

[C]. aL

[D]. AL

Q11. The chemical formula of a molecular compound is determined by

[A]. Atomic mass of the element

[B]. Reactivity of the element

[C]. Valency of each element

[D]. Alphabetical sequence of the element

Q12. Atoms of a given element are identical

[A]. In shape and chemical properties

[B]. In shape and physical properties

[C]. In mass and chemical properties

[D]. Valency of each element

Chemical Formulas in 9th Chemistry MCQ

Writing chemical formulas correctly is a good skill covered in Class 9 Science Chapter 3 Important Questions. Understanding how elements combine to form compounds is fundamental in chemistry. The Atoms and Molecules Class 9 Important Questions focus on valency, molecular formulas and chemical bonding. In Class 9 Science Chapter 3 Worksheet, students practice writing chemical equations and determining reactant-product compositions. The Atoms and Molecules Class 9 Worksheet provides exercises on ionic and covalent bonds, oxidation states and molecular geometry. Lastly, solving Class 9 Science Chapter 3 MCQ with Answers reinforces these concepts, ensuring students develop a scientific approach to chemical problem-solving.

Q13. The relative mass of a molecule is expressed in

[A]. Grams

[B]. Molecular units

[C]. Atomic mass units

[D]. Milligrams

Q14. The first atomic theory was put forward by

[A]. Newton

[B]. Lavoisier

[C]. Democritus

[D]. John Dalton

What are the key topics covered in Class 9 Science Chapter 3 MCQ?

Class 9 Science Chapter 3 MCQ primarily focuses on the fundamental concepts of atoms and molecules, their properties and their role in chemical reactions. It covers required topics like Dalton’s Atomic Theory, the law of conservation of mass, the law of constant proportions, atomic structure, molecular composition and the mole concept. The Atoms and Molecules Class 9 MCQ section often includes questions on calculating atomic and molecular masses, determining empirical and molecular formulas and balancing chemical equations. Class 9 Science Chapter 3 Multiple Choice Questions test a student’s understanding of atomic models and experimental findings that shaped modern chemistry.

Why is the mole concept important in Atoms and Molecules Class 9?

The mole concept is an important part of Atoms and Molecules Class 9 Questions as it helps in quantifying chemical substances in reactions. A mole represents 6.022 × 10^23 atoms, molecules or ions, known as Avogadro’s number. It allows chemists to relate the mass of a substance to the number of particles present. Class 9 Science Chapter 3 Practice Questions often require students to calculate the number of moles from given mass, determine molar mass and use stoichiometry to balance chemical reactions. Understanding this concept is essential for solving Class 9 Science Chapter 3 Objective Questions, as it forms the basis for many real-world applications in chemistry.

How can students prepare effectively for Class 9 Science Chapter 3 MCQ?

To master Class 9 Chemistry Chapter 3 MCQ, students should focus on conceptual clarity and practice problem-solving techniques. They should thoroughly study the Class 9 Science Chapter 3 Notes to understand atomic structure, molecular composition and chemical laws. Practicing Atoms and Molecules Class 9 Worksheet helps in reinforcing concepts like valency, balancing chemical equations and calculating molar masses. Attempting Class 9 Science Chapter 3 MCQ with Answers allows students to familiarize themselves with question patterns and improve accuracy. Regular revision using Atoms and Molecules Class 9 PDF ensures better retention and enhances performance in exams.