Class 9 Science Chapter 8: Journey Inside the Atom — practice questions with answers
Free practice for Class 9 Science, Chapter 8: Journey Inside the Atom. Try the solved questions below, then take a free test with instant marking and explanations.
54 questions21 easy, 20 medium, 13 hardNCERT · CBSE · State boards
Sample questions with solutions
Q1. In the gold foil experiment, most alpha particles passed straight through. What did this show?
- Most of the atom is empty space
- The atom is solid throughout
- Electrons are heavy
- Gold has no atoms
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Answer: A. Most of the atom is empty space
Why: A few bounced back. [p.143–144]
Why: A few bounced back. [p.143–144]
Q2. If an atom were the size of a cricket ground, the nucleus would be about the size of ______.
- a grain of black pepper at the centre
- a football
- the pitch
- a car
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Answer: A. a grain of black pepper at the centre
Why: Shows how tiny the nucleus is. [p.144]
Why: Shows how tiny the nucleus is. [p.144]
Q3. Why do scientists use symbols like Na and K instead of full names?
- They are internationally recognised and work across languages
- They are shorter in Hindi
- They are secret codes
- They are more colourful
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Answer: A. They are internationally recognised and work across languages
Why: Na from natrium, K from kalium. [p.149]
Why: Na from natrium, K from kalium. [p.149]
Q4. What does the atomic number (Z) of an element tell us?
- The number of protons in its atoms
- The number of neutrons
- The total of protons and neutrons
- Its mass in grams
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Answer: A. The number of protons in its atoms
Why: In a neutral atom it also equals the number of electrons. [p.149–150]
Why: In a neutral atom it also equals the number of electrons. [p.149–150]
Q5. An atom has 79 protons and mass number 197. How many neutrons does it have?
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Answer: 118 (± 0)
Why: 197 − 79 = 118. [p.160]
Why: 197 − 79 = 118. [p.160]
Q6. An atom with mass number 70 has 31 electrons. How many neutrons does it have?
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Answer: 39 (± 0)
Why: Protons = electrons = 31; neutrons = 39. [p.160]
Why: Protons = electrons = 31; neutrons = 39. [p.160]
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Frequently asked questions
How many practice questions are there for Class 9 Science Chapter 8: Journey Inside the Atom?
54 questions (21 easy, 20 medium, 13 hard). A few are solved on this page; the free test shows the answer and explanation for every question after you submit.
Is this chapter from the NCERT book?
Yes — it follows the NCERT Class 9 Science syllabus, used by CBSE and many state boards.