MCQ Basic Units of Matter Chapter 3 Class 9 Science Advertisement MCQ’s For All Chapters – Science Class 9th 1. What are the building blocks of matter?CompoundMoleculesAtoms ElementYour comments:Question 1 of 142. How do atoms usually exist in nature?In the form of moleculesIn the form of ionsIn the free stateIn the form of molecules and IonsYour comments:Question 2 of 143. Which atom is the smallest atom of all? LithiumHeliumHydrogenCarbonYour comments:Question 3 of 144. Which of the following can be used to see atoms?Scanning tunneling microscopeMicroscopeMost powerful microscope Optical microscopeYour comments:Question 4 of 145. The number of atoms present in one molecule of an element is called as: Empirical formula MoleculeAtomicityCompoundYour comments:Question 5 of 146. Out of the following, which one is an example of a molecule of a compound?Water moleculeOxygen moleculeOzoneNitrogen moleculeYour comments:Question 6 of 147. Cl2 stands for:2 molecules of chlorine2 atoms of chlorine2 ions of chlorine3 molecule of chlorineYour comments:Question 7 of 148. Which constituent of air is monoatomic?ArgonWater vapourOxygenNitrogenYour comments:Question 8 of 149. Molecules can exist in free state because:They are very stable.They are electrically charged.They are very reactive.They are bigger in size as compared to atoms.Your comments:Question 9 of 1410. Which is the smallest particle of an element that can take part in a chemical reaction?MoleculeMixtureCompoundAtomYour comments:Question 10 of 1411. Assertion: Atoms always combine to form molecule and ions. Reason: Atoms of most element are not able to exist independently.a.) Both Assertion and Reason are correct, and reason is the correct explanation for assertion.b.) Both Assertion and Reason are correct, and Reason is not the correct explanation for Assertion.c.) Assertion is true but Reason is false.d.) Assertion is false but Reason is trueQuestion 11 of 1412. Assertion: Atomicity of ozone is three while that of oxygen is two. Reason: Atomicity is the number of atoms constituting a molecule.a.) Both Assertion and Reason are correct, and reason is the correct explanation for assertion.b.) Both Assertion and Reason are correct, and Reason is not the correct explanation for Assertion.c.) Assertion is true but Reason is false.d.) Assertion is false but Reason is trueQuestion 12 of 1413. Assertion : Molecular weight of oxygen is 16. Reason : Atomic weight of oxygen is 16.a.) Both Assertion and Reason are correct, and reason is the correct explanation for assertion. b.) Both Assertion and Reason are correct, and Reason is not the correct explanation for Assertion. c.) Assertion is true but Reason is false. d.) Assertion is false but Reason is true Question 13 of 1414. Assertion : The number of moles of He in 52 g of He is 13. Reason : The number of moles of an atom is the ratio of its given mass to its molar mass.a.) Both Assertion and Reason are correct, and reason is the correct explanation for assertion. b.) Both Assertion and Reason are correct, and Reason is not the correct explanation for Assertion. c.) Assertion is true but Reason is false.d.) Assertion is false but Reason is true Question 14 of 14 Loading...
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