Last Updated on May 15, 2025 by XAM CONTENT
Understanding the key concepts of Class 9 Science Chapter 4 – Structure of the Atom is crucial for exam success. To make your revision easier, we have created chapterwise mcq questions with Answers for class 9 Science based on the latest syllabus and exam pattern. It is a part of MCQ Questions for CBSE Class 9 Science Series.
These multiple-choice questions will help you assess your knowledge, improve accuracy, and boost confidence for your exams. Whether you are preparing for school tests, online tests or competitive exams, these Structure of the Atom MCQs will strengthen your conceptual clarity.
| Chapter | Structure of the Atom |
| Book | Science Textbook for Class 9 |
| Type of Questions | MCQ Questions |
| Nature of Questions | Competency Based Questions |
| Board | CBSE |
| Class | 9 |
| Subject | Science |
| Useful for | Class 9 Studying Students |
| Answers provided | Yes |
| Difficulty level | Mentioned |
| Important Link | Class 9 Science Chapterwise MCQ Questions |
MCQ Questions on Structure of the Atom Class 9 Science
MCQs
Q1. Which experiment led to the discovery of the atomic nucleus?
(a) Cathode ray experiment
(b) Alpha particle scattering experiment
(c) Electrolysis of water
(d) Law of conservation of mass
Show Answer
Answer: (b)
Explanation: Rutherford’s alpha particle scattering experiment revealed the existence of the dense, positively charged nucleus.
Q2. Why was Rutherford’s model of the atom considered incomplete?
(a) It didn’t explain the presence of electrons
(b) It couldn’t explain atomic spectra
(c) It violated the law of inertia
(d) It assumed atoms are indivisible
Show Answer
Answer: (b)
Explanation: Rutherford’s model couldn’t explain why revolving electrons did not radiate energy and collapse into the nucleus.
Q3. What is the significance of neutrons in an atom?
(a) They balance charge
(b) They contribute to atomic mass
(c) They determine chemical properties
(d) They occupy the outermost shell
Show Answer
Answer: (b)
Explanation: Neutrons are neutral particles in the nucleus that contribute to the atom’s mass but not its charge.
Q4. What is the electronic configuration of an element with atomic number 17?
(a) 2, 8, 7
(b) 2, 8, 8
(c) 2, 7, 8
(d) 2, 6, 9
Show Answer
Answer: (a)
Explanation: Chlorine has 17 electrons: 2 in K-shell, 8 in L-shell, and 7 in M-shell (2, 8, 7).
Q5. Which of the following correctly describes isotopes?
(a) Same atomic number, same mass number
(b) Different atomic number, same mass number
(c) Same atomic number, different mass number
(d) Same neutrons, different protons
Show Answer
Answer: (c)
Explanation: Isotopes have the same number of protons (atomic number) but different numbers of neutrons (mass number).
Q6. Which sub-atomic particle determines the identity of an element?
(a) Neutron
(b) Proton
(c) Electron
(d) Nucleus
Show Answer
Answer: (b)
Explanation: The number of protons (atomic number) defines the identity of an element.
Q7. Which statement is true about Bohr’s model?
(a) Electrons can exist anywhere around the nucleus
(b) Electrons radiate energy while moving in fixed orbits
(c) Electrons move in fixed energy levels
(d) Protons revolve around electrons
Show Answer
Answer: (c)
Explanation: According to Bohr, electrons move in fixed orbits and do not radiate energy while in those orbits.
Q8. Which of these particles has negligible mass?
(a) Proton
(b) Neutron
(c) Electron
(d) Nucleus
Show Answer
Answer: (c)
Explanation: The electron has negligible mass compared to protons and neutrons.
Q9. What is the valency of sulphur with atomic number 16?
(a) 4
(b) 2
(c) 6
(d) 3
Show Answer
Answer: (b)
Explanation: Sulphur (2,8,6) needs 2 more electrons to complete octet, hence valency = 2.
Q10. What will be the average atomic mass of chlorine with isotopes 35Cl (75%) and 37Cl (25%)?
(a) 36.5 u
(b) 35 u
(c) 37 u
(d) 34.5 u
Show Answer
Answer: (a)
Explanation: Average mass = (75×35 + 25×37)/100 = 2625+925 = 3550/100 = 35.5 u.
We hope the given mcq questions with Answers for Structure of the Atom Class 9 helps you in your learning.
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Topics from which mcq questions may be asked
- Structure of an atom
- Atomic models
- Valency and isotopes
Understanding atoms gives us insights into the universe’s tiniest constituents.
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Frequently Asked Questions (FAQs) on Structure of the Atom MCQ Questions
Q1: What are MCQ questions in Class 9 Science?
A1: MCQ (Multiple Choice Questions) in Class 9 Science are objective-type questions where students choose the correct answer from four options. They test conceptual understanding, application, and reasoning skills.
Q2: Are these Class 9 Science MCQs based on the latest CBSE syllabus?
A2: Yes, all MCQ questions provided are strictly based on the latest CBSE Class 9 Science syllabus and follow the current NCERT textbook.
Q3: Are Class 9 Science MCQ questions useful for board exam preparation?
A3: Yes, practicing MCQ questions helps build strong conceptual understanding and improves performance in school tests, Olympiads, and board-level competency assessments.
Q4: Do these MCQs include answers and explanations?
A4: Absolutely. Each MCQ question includes the correct answer along with a detailed explanation to help students understand the concept behind the question.
Q5: Where can I find the best MCQ questions for Class 9 Science?
A5: You can find high-quality, CBSE-based MCQ questions for Class 9 Science on trusted educational websites like xamcontent.com. These include chapterwise, topicwise, and competency-based questions aligned with the latest syllabus
Q6: Are there any resources available online for students to practice mcq questions on class 9 science chapter 4 “Structure of the Atom“ for CBSE exams?
A6: Yes, several educational websites offer mcq questions for CBSE students preparing for science examinations. We also offer a collection of mcq questions for all classes and subject on our website. Visit our website to access these questions and enhance your learning experience. for more mcq, you can also visit Physics Gurukul Website.
