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Class 9

Explore popular questions from Structure of Atoms for Class 9. This collection covers Structure of Atoms previous year Class 9 questions hand picked by experienced teachers.

Structure of Atoms

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Q 1. An atom with atomic number 18 and mass number 40, has the following arrangement

18p, 18e, 22n

B

18p, 18e, 40n

C

22p,18e, 18n

D

22p,22e,18n

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Q 2. The isotope of carbon used in radiocarbon dating is

A

162C

B

163C

164C

D

165C

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Q 3. Which one of the following is correct electronic configuration of sodium ?

A

2,8

B

8,2,1

C

8,2

2,8,1

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Q 4. Particle in cathode rays have same charge to mass ratio as

A

particles

rays

C

rays

D

Protons

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Q 5. Which of the following particles has maximum charge to mass ratio ?

Electrons

B

Protons

C

{tex}\alpha-{/tex}particle

D

Neutrons

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Q 6. Which of the following pairs of species are iso-electronic ?

A

H2O, H2S

{tex}\mathrm{NO_{3}^{-}}{/tex},{tex}\mathrm{CO_{3}^{2-}}{/tex}

C

H3O+, K+

D

HF, HCI

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Q 7. Which of the following traids represents isotones ?

A

6C12, 6C13, 6C14

18Ar40, 20Ca42, 21Sc43

C

18Ar40, 20Ca40, 21Sc41

D

7N14, 8O16, 9F19

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Q 8. Which of the following statements is correct ?

{tex} _{7}N^{14}{/tex} and {tex}_{6}C^{13}{/tex} are isotones

B

{tex} _{7}N^{14}{/tex} and {tex}_{6}C^{14}{/tex} are isotopes

C

{tex} _{7}N^{14}{/tex} and {tex}_{6}C^{12}{/tex} are isobars

D

{tex} _{7}N^{14}{/tex} and {tex}_{6}C^{15}{/tex} are isotones

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Q 9. Which of the followings statement is not correct ?

A

Isotones are atoms of different elements having same number of neutrons

B

Isotopes are atoms of differenet elements having same number of protons

Isobars are atoms of different elements having same number of neutrons

D

Isotones and isobars are atoms of different elements

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Q 10. When atoms of the gold sheet are bombarded by a beam of &-particles, only a few &-particles get deflected whereas most of them go straight undeflected This is because:

A

the force of attraction on &-particles by the oppositely charged electron is not sufficient

the nucleus occupies much smaller volume as compared to the volume of atom

C

the force of repulsion on fast moving &-particles is very small

D

the neutrons in the nucleus do not have any effect on &-particles

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Q 11. A region in space around the nucleus of an atom where the probability of finding the electron is maximum is called

A

sub-level

B

orbit

orbital

D

electron shell

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Q 12. The possible sub shells in n = 3 energy shell are

s, p, d

B

s, p, d, f

C

s, p

D

s only

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Q 13. Which of the following orbital does not make sense?

A

3d

3f

C

5p

D

7s

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Q 14. The maximum number of electrons with clockwise spin that can be accomodated in a f-subshell is

A

10

B

3

C

5

7

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Q 15. Indicate which electronic configuration amongst the following correctly represent SULPHUR atom ?

A

1s22s22p63s23p23d2

B

1s22s22p63s23p24s2

C

1s22s22p63s23p64s14p1

1s22s22p63s23p4

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Q 16. As we move away from nucleus, the energy of orbit

A

decreases

increases

C

remains unchanged

D

none of these

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Q 17. Electronic configuration of calcium atom can be written as

A

[Ne] 4p2

[Ar] 4] 4s2

C

[Ne] 4s2

D

[Kr] 4p2

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Q 18. Which one of the following pairs of atoms/atom-ion have identical ground state configuration ?

A

Li+ and He+

Cl- and Ar

C

Na and K

D

F+ and Ne

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Q 19. The correct electronic configuration of Cu(29) is

1s22s22p63s23p63d104s1

B

1s22s22p63s23p53d114s1

C

1s22s22p63s33p63d94s2

D

1s22s22p63s23p53d104s2

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Q 20. The number of d-electrons in Fe2+ (atomic number = 26) is equal to that of

p-electrons in 10Ne

B

s-electrons in 12Mg

C

d-electrons in Fe

D

p-electrons in Cl

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Q 21. Which of the following is the electronic configuration of Cu2+ (Z = 29) ?

A

[Ar]4s13d10

B

[Ar]4s23d104p1

C

[Ar]4s13d10

[Ar]3d9

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Q 22. Unpaired electrons in Ni++, (Z = 28) is

A

0

2

C

4

D

8

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Q 23. Which of the following electronic configurations is not possible according to Hund's rule ?0

A

1s22s2

B

1s22s1

C

1s22s22p12p12p1

1s22s22p12p22p0

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Q 24. Which of the following statement are wrong ?

A

An atom is electrically neutral

An atom & its ion have an unequal number of protons

C

The size of a cation is smaller than that of corresponding atom

D

An atom & its corrosponding anion have equal number of electrons

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Q 25. Which of the following sub-atomic particles is/are present in the nucleus of an atom?

proton

B

electron

C

positron

D

meson