MULTIPLE CHOICE QUESTIONS:

CLASS 9 SCIENCE 3: ATOMS AND MOLECULES MULTIPLE CHOICE QUESTIONS:
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MULTIPLE CHOICE QUESTIONS( MCQ’s)

1. The charged particles (atoms) are called __________.

(a) Atomicity
(b) Ions
(c) Cations
(d) Anions

2. The ________ of a compound is a symbolic representation of its composition.

(a) Chemical Formula
(b)  Solubility 
(c) Composition 
(d) Dissociation

3. The combining capacity of an element is called as its _____.

(a)  Formula
(b) Isotope
(c) Valency
(d) Molecule

 4.  ____________ is the smallest particle of an element or a compound which can exist independently.

(a) Isotope
(b) Cation
(c) Ion 
(d) Molecule

5. The number of atoms constituting a molecule is called ____________.

(a) Atomicity
(b) Isotope
(c) Formula
(d) Mass

6. The valency of nitrogen in NH3 is ___________.

(a) 2
b) 3
(c) 4
(d) 5

7. Which of the following would weigh the highest?
(a) 0.2 mole of sucrose (C12H22O11)
(b) 2 moles of CO2
(c) 2 moles of CaCO3
(d) 10 moles of H2O

8. The symbol of Cadmium is _____

(a) Ca
(b) Cu
(c) Cm
(d) Cd

9. The smallest particle of matter, which can take part in a chemical reaction is called ___________.

(a)  Molecule
(b) Atom
(c)  Ion
(d) Anion

10. Atoms exist in the form of _______,________, or __________.

(a) Atom, Molecule, Ion
(b) Molecule, Ion,Mole
(c) Atom, Molecule ,Mole
(d) Mole, Ion, Anion

11. When the atomic mass of an element is expressed in grams, it is called _______.

(a) Gram atomic mass
(b) Molecular mass 
(c)  Atomic mass
(d) Gram mass

12. The ions which contain more than one atoms and behave as a single unit is called ____________.

(a)  Cations
(b) Anions
(c) Polyatomic ions 
(d) Diatomic ions

13. __________ is the sum of the atomic masses of all the atoms in a molecule of the substance.

(a)  Atomic mass
(b) Gram atomic mass
(c) Gram mass
(d) Molecular mass

14. Molecules of an element constitutes same type of ___________.

(a) Ions
(b) Atoms
(c) Moles
(d) Cations

 15. Who coined the term atom?

(a) John Dalton
(b) Neils Bohr
(c) Mosley
(d) Ernest Rutherford

16. Which of the following has maximum number of atoms?
(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g 0f CH4

17. 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

18. Percentage of calcium in calcium carbonate is ____
(a) 40
(b) 30
(c) 48
(d) 36

19. Which has maximum number of molecules?
(a) 1 g of CO2
(b) 1 g of N2
(c) 1 g of H2
(d 1 g of CH4

20. What mass of carbon dioxide (CO2) will contain 3.011 × 1023 molecules?
(a) 11.0 g
(b) 22.0 g
(c) 4.4 g
(d) 44.0 g

21. The value of Avogadro’s constant is:  ___
(a) 6.0 × 1024
(b) 6.01 × 1022
(c) 6.022 × 1023
(d) 6.022 × 10-23

22. 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

23. The number of oxygen atoms in 4.4 g of CO2 is approx. ____
(a) 6 × 1022
(b) 6 × 1023
(c) 12 × 1023
(d) 1.2 × 1023

24. Which of the following represents 12 u?
(a) Mass of 1 hydrogen atom
(b) Mass of C−12 atom
(c) Mass of 0−16 atom
(d) 1/12th of mass of C−12 atom.

25. The molecule having an atomicity of 4 is ____
(a) Sulphate molecule
(b) Ozone molecule
(c) Phosphorus molecule
(d) Methane molecule

26. ______ was the first scientist to use the symbols for elements in a specific way
a) John Dalton
b) Neils Bohr
c) Mosley
d) Ernest Rutherford

27. _______ forms molecules and ions.
a) Ions
b) Atoms
c) Moles
d) Cations

28. A group of atoms carrying a charge is called as a ______ion.
a)  Carbonate
b) Polyatomic
c) Molecular
d) None of these
 
29. Formula unit mass is calculated in the same manner as we calculate the ______ mass.
a)  Carbonate
b) Polyatomic
c) Molecular
d) Atomic

30. Mass of one mole of a substance is called as its _____ mass
a) Molar
b) Polyatomic
c) Molecular
d) Atomic

Answers:
1. (b) Ions
2. (a) Chemical Formula
3. (c) Valency
4. (d) Molecule
5. (a) Atomicity
6. (b) 3
7. (c) 2 moles of CaCO3
8. (d) Cd
9. (b) Atom
10. (a) Atom, Molecule, Ion
11. (a) Gram atomic mass
12. (c) Polyatomic ions
13. (d) Molecular mass
14. (b) Atoms
15. (a) John Dalton
16. (d) 18 g 0f CH4
17. (c) When energy is either given to, or taken out from the system
18. (a) 40
19. (c) 1 g of H2
20. (b) 22.0 g
21. (c) 6.022 × 1023
22. (c) 8/3 times
23. (d) 1.2 × 1023
24. (d) 1/12th of mass of C−12 atom.
25. (c) Phosphorus molecule
26. (a) John Dalton
27. (b) Atoms
28. (b) Polyatomic
29. (c) Molecular
30. (a) Molar

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