Class 9 Science — Chapter 4: Is Matter Around Us Pure?
90 practice questions · 30 Easy · 30 Medium · 30 Hard
Practise Class 9 Science Chapter 4, "Is Matter Around Us Pure?", with 90 NCERT-aligned multiple-choice questions. The set is split into 30 Easy, 30 Medium and 30 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams and the JEE & NEET foundation years.
"Is Matter Around Us Pure?" is one of the chapters where concept clarity across physics, chemistry and biology basics really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Is Matter Around Us Pure?, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 9 Science mastery score. A few sample questions are shown below; sign in free to practise all 90.
Key concepts: Is Matter Around Us Pure? (Class 9 Science)
This chapter traces atomic models from Thomson to Bohr, describes the sub-atomic particles, and explains electronic configuration, valency, atomic number and isotopes.
- Sub-atomic particles
- Protons (+, in the nucleus), neutrons (neutral, in the nucleus) and electrons (−, around the nucleus). Almost all the mass is in the nucleus.
- Atomic models
- Thomson's plum-pudding, Rutherford's nuclear model (from the α-scattering experiment), and Bohr's model with electrons in fixed energy shells.
- Electron distribution
- Electrons fill shells K, L, M, N… following the 2n² rule, with the outermost shell holding at most 8 electrons.
- Valency
- Decided by valence (outermost) electrons — the number of electrons gained, lost or shared to complete the octet.
- Atomic number & mass number
- Atomic number Z = number of protons; mass number A = protons + neutrons.
- Isotopes & isobars
- Isotopes have the same Z but different A (e.g. C-12, C-14); isobars have the same A but different Z.
Key formulas — Is Matter Around Us Pure?
💡 Exam tips for Is Matter Around Us Pure?
- The outermost shell never holds more than 8 electrons, even though 2n² may allow more.
- Isotopes = same protons, different neutrons; isobars = same mass number, different elements.
Sample questions
A homogeneous mixture is also called a:
Homogeneous mixture has uniform composition — that's a solution.
A solution containing 10 g salt in 90 g water has mass percentage of salt:
Mass % = (10 / (10+90)) × 100 = 10%.
The Tyndall effect (scattering of light) is observed in:
Colloid particles are large enough to scatter light — Tyndall effect.
Is Matter Around Us Pure? — FAQs
What are the key concepts in Class 9 Science Is Matter Around Us Pure??+
This chapter traces atomic models from Thomson to Bohr, describes the sub-atomic particles, and explains electronic configuration, valency, atomic number and isotopes. Key ideas include Sub-atomic particles, Atomic models, Electron distribution, Valency, Atomic number & mass number.
What does Class 9 Science Chapter 4 (Is Matter Around Us Pure?) cover on XamBaaz?+
It covers 90 NCERT-aligned MCQs on "Is Matter Around Us Pure?" — 30 Easy, 30 Medium and 30 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams and the JEE & NEET foundation years.
Are these "Is Matter Around Us Pure?" questions free to practise?+
Yes — sign in with Google to practise "Is Matter Around Us Pure?" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Is Matter Around Us Pure?" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
Practise all 90 questions free
Timed quizzes, instant scoring, streaks and XP. Sign in with Google — no card needed.
Start this chapter free →