MCQ & Online Test – Structure of the Atom – NCERT Class 9 Science Chapter 4

Online Test | MCQ Structure of the Atom | NCERT Class 9 Science Chapter 4 | CBSE Syllabus

Every student of class 9 of NCERT/CBSE syllabus may take part this online test of NCERT Class 9 Science Chapter 4 MCQ Structure of the Atom and verify his score to check preparedness

#1. The number of electrons in an element X is 15 & the number of neutrons is 16. Which of the following is the correct representation?

a) ³¹X₁₅

a) ³¹X₁₅

a) ³¹X₁₆

a) ³¹X₁₆

c) ¹⁶X₁₅

c) ¹⁶X₁₅

d) ¹⁵X₁₆

d) ¹⁵X₁₆

#2. Rutherford's alpha(∝) particles scattering experiment resulted in to discovery of

a) electron

a) electron

b) proton

b) proton

c) nucleus in the atom

c) nucleus in the atom

d) atomic mass

d) atomic mass

#3. Which of the following represents the electronic distribution of Mg atom?

a) 3, 8, 1

a) 3, 8, 1

b) 2, 8, 2

b) 2, 8, 2

c) 1, 8, 3

c) 1, 8, 3

d) 8, 2, 2

d) 8, 2, 2

#4. Elements with valency 1 are

a) always metals

a) always metals

b) always metalloids

b) always metalloids

c) either metals or non-metals

c) either metals or non-metals

d) always non-metals

d) always non-metals

#5. The electron distribution in an aluminium atom is -

a) 2, 8, 3

a) 2, 8, 3

b) 2, 8, 2

b) 2, 8, 2

c) 8, 2, 3

c) 8, 2, 3

d) 2, 3, 8

d) 2, 3, 8

#6. Select the option where both are correct - a) atomic no. = no. of protons + no. of electron, b) mass no. = no. of protons + no. of neutron, c) atomic mass = no. of protons = no. of neutrons, d) atomic no. = no. of protons = no. of electron?

a) & c)

a) & c)

b) & d)

b) & d)

c) & d)

c) & d)

b) & c)

b) & c)

#7. Isotopes of an element have

a) same physical properties

a) same physical properties

b) different chemical properties

b) different chemical properties

c) different atomic numbers

c) different atomic numbers

d) different number of neutrons

d) different number of neutrons

#8. Arrange a. Rutherford's atomic model, b. Thomson's atomic model, c. Bohr's atomic model, in the order of their chronological order.

a, b, c

a, b, c

b, c, a

b, c, a

b, a, c

b, a, c

c, b, a

c, b, a

#9. The correct electron configuration of sodium is -

a) 2, 8

a) 2, 8

b) 8, 2, 1

b) 8, 2, 1

c) 2, 1, 8

c) 2, 1, 8

d) 2, 8, 1

d) 2, 8, 1

#10. Which are correct about Thompson's model of atom - a. the mass of the atom is assumed to be uniformly distributed over the atom, b. the positive charge is assumed to be uniformly distributed over the atom, c. the electrons are uniformly distributed in the positively charged sphere, d. the electrons attract each other to stabilize the atom ?

a, b, c

a, b, c

a, c

a, c

a, d

a, d

a, c, d

a, c, d

#11. Which of the following statements are correct about Rutherford's model of atom - a. considered the nucleus as positively charged, b. established that α-particles are four times as heavy as a hydrogen atom, c. can be compared to solar system, d. was in agreement with Thompson's model??

a, c

a, c

b, c

b, c

a, d

a, d

a

a

#12. Which are correct about Rutherford's α-particle scattering experiment - a. electrons have negative charge, b. the mass & positive charges of the atom is concentrated in the nucleus, c. neutron exists in the nucleus, d. most of the space in the atom is empty ?

a, c

a, c

b, d

b, d

a, d

a, d

c, d

c, d

#13. Rutherford's α-particle scattering experiment was responsible for the discovery of -

a) atomic nucleus

a) atomic nucleus

b) electron

b) electron

c) proton

c) proton

d) neutron

d) neutron

#14. An atom with 3 protons & 4 neutrons will have a valency of

a) 3

a) 3

b) 7

b) 7

c) 1

c) 1

d) 4

d) 4

#15. Which of the following statement is always correct

a) an atom has equal no. of electrons & protons

a) an atom has equal no. of electrons & protons

b) an atom has equal no. of electrons & neutrons

b) an atom has equal no. of electrons & neutrons

c) an atom has equal no. of neutrons & protons

c) an atom has equal no. of neutrons & protons

d) an atom has equal no. of electrons, protons & neutrons

d) an atom has equal no. of electrons, protons & neutrons

#16. The ion of an element has 3 +ve charges. Mass no. of the atom is 27. No. of neutrons is 14. What is the no. of electrons in the ion?

a) 13

a) 13

b) 10

b) 10

c) 14

c) 14

d) 16

d) 16

#17. Which figures do not represent Bohr's atomic model correctly?

a & c

a & c

b & c

b & c

b & d

b & d

a & d

a & d

#18. The first model of an atom was given by

a) N. Bohr

a) N. Bohr

b) E. Goldstein

b) E. Goldstein

c) Rutherford

c) Rutherford

d) J. J. Thompson

d) J. J. Thompson

#19. Which of the following are true for an element - a) atomic no. = no. of protons + no. of electrons, b) mass no. = no. of protons + no. of neutrons, c) atomic mass = no. of protons = no. of neutrons, d) atomic no. = no. of protons = no. of electrons

a) & b)

a) & b)

a) & c)

a) & c)

b) & c)

b) & c)

b) & d)

b) & d)

#20. Number of valence electron in Cl^- are -

a) 16

a) 16

b) 8

b) 8

c) 17

c) 17

d) 18

d) 18

#21. In a sample of ethyl ethanoate (CH₃COOC₂H₅), the two oxygen atoms have the same no. of electrons but different no. of neutrons. Which of the following statement is correct?

a) one of the oxygen atoms has gained electrons

a) one of the oxygen atoms has gained electrons

b) one of the oxygen atoms has gained two neutrons

b) one of the oxygen atoms has gained two neutrons

c) the two oxygen atoms are isotopes

c) the two oxygen atoms are isotopes

d) the two oxygen atoms are isobars

d) the two oxygen atoms are isobars

#22. Identify the Mg²⁺ ion from the following figure where n = no. of neutrons & p = no. of protons.

a

a

b

b

c

c

d

d

#23. Dalton's atomic theory successfully explained - a. law of conservation of mass, b. law of constant composition, c. law of radioactivity, d. law of multiple proportion.

a, b, c

a, b, c

a, c, d

a, c, d

b, c, d

b, c, d

a, b, d

a, b, d

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To Be Continued