Atom and molecules class 9 mcq

Atom and molecules class 9 mcq with answers pdf

Here you will find a list of Most important Multiple Choice Questions on Atom and molecules with answer for competitive exams like CBSE Class 9 science chapter 3 MCQs . These frequently asked sample questions on are given with correct choice of answer that you can check instantly. Presently we have added more than 30 MCQ questions on class 8 science chapter 3 for your practice. We will keep adding more questions and provide this question bank in PDF format, so that you can download them instantly in E-book style.

Atom and molecules class 9 mcq

MCQs Atom and molecules class 9

1. Which of the following statements is not true about an atom?

(a) Atoms are not able to exist independently.

(b) Atoms are the basic units from which molecules and ions are formed.

(c) Atoms are always neutral in nature.

(d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.

Answer: D

2. Which of the following contains maximum number of molecules?

(a) 19 CO2

(b) 1 g N2

(c) 1 g H2

(d) 1 g CH4

Answer: C

3. The molecular formula of potassium nitrate is ________

(a) KNO3

(b) KNO

(c) KNO2

(d) KON

Answer: A 

4. Laws which explain the formation of many oxides by nitrogen is_______

(a) Law of conservation of mass

(b) Law of multiple proportions

(c) Law of definite proportions

(d) Avogadro’s law

Answer: B

5. Which pairs of elements have gram molecular mass same as gram atomic mass?

(a) Argon, Nitrogen

(b) Fluorine, Magnesium

(c) Phosphorus, Gold

(d) Silicon, Neon

Answer: D

6. From which oxyacid two acidic radicals can be derived.

(a) Phosphoric acid

(b) Sulphurous acid

(c) Nitric acid

(d) Chlorous acid

Answer: B

7. When alpha-particles are sent through a thin metal foil, most of them go straight through the foil because, _______

(a) alpha-particles are much smaller than electrons.

(b) alpha-particles are positively charged

(c) most part of the atom is empty space

(d) alpha-particles move with a low velocity

Answer: C

8. The chemical symbol for nitrogen gas is____

(a) Ni

(b) N2

(c) N+

(d) None of the above

Answer : B

9. A change in the physical state can be brought about_____

(a) only when energy is given to the system

(b) only when energy is taken out from the system

(c) when energy is either given to or taken out from the system

(d) without any energy change

Answer : C

10. The most remarkable concept that Dalton’s atomic theory proposed was that of the_______

(a) atomic weight

(b) atomic mass

(c) molar mass

(d) none of them

Answer: B

11. 1 u or 1 amu means_______

(a) 1/12th mass of C-12 atoms

(b) Mass of C-12 atom

(c) Mass of O-16 atom

(d) Mass of Hydrogen molecule

Answer: A

12. The word “mole” was introduced around 1896 by______

(a) Wilhelm Ostwald

(b) John Dalton

(c) Avogadro

(d) Vergilious

Answer: A.

13. Who coined the term ‘Parmanu’ for the smallest indivisible particles?

(a) Leucippus

(b) L. Lavoisier

(c) Kanad

(d) None of them

Answer: C

14. Compounds composed of metals and non-metals contain________

(a) non-charged species

(b) charged species

(c) both of them

(d) none of them

Answer: B

15. Molecular mass is defined as the:

(a) Mass of one molecule of any substance compared with the mass of one atom of C – 12

(b) Mass of one atom compared with the mass of one atom of hydrogen

(c) Mass of one atom compared with the mass of one molecule

(d) None of the above

Answer: A

16. Which of the following has maximum number of atom?

(a) 18 g H2O

(b) 18 g of O2

(c) 18 g of CO2

(d) 18 g of CH4

Answer: D

17. The value of Avogadro’s constant is:

(a) 6.0 × 10²⁴

(b) 6.01 × 10²²

(c) 6.022 × 10²³

(d) 6.022 × 10-²³

Answer: C

18. The molecule having an atomicity of 4 is______

(a) Sulphate molecule

(b) Ozone molecule

(c) Phosphorus molecule

(d) Methane molecule

Answer: C

19. How many times an atom of sulphur is heavier than an atom of carbon?

(a) 32 times

(b) 12 times

(c) 8/3 times

(d) 12/32 times

Answer: C

20. Which of the following represents a correct chemical formula?

(a) CaCl

(b) BiPO4

(c) NaSO4

(d) NaS

Answer. B

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