CLASS XI MCQ TEST

1. The atomic number of the element having maximum number of unpaired 3p electrons is (in ground state)

15

10

12

8

2. In an electronic transition atom cannot emit

Visible light

Gamma rays

Infra red light

UV light

3. Which orbital diagram does not obey Aufbau Principle?

A

B

C

D

4. If the Planck's constant h= 6.6 m 10^-34Js , de Broglie wavelength of a particle having momentum of 3.3m 10^-24kg m s^-1will be

0.02 A°

0.5 A°

2 A°

500 A°

5. An electron has kinetic energy 2.8m10^-23 J De-broglie wavelength will be nearly?

9.8×10-24

9.8×10-7

9.8×10-8

9.8×10-10

6. The kinetic energy of the electron emitted when light of frequency 3.5 m 10¹⁵Hz is thrown on a metal surface having threshold frequency 1.5m10¹⁵Hz is ( h= 6.6 m 10^-34J/s)

1.32 × 10-18 J

3.3 × 10-18 J

6.6 × 10-19 J

1.98 × 10-19 J

7. Which of the following statements does not form a part of Boards model of hydrogen atom?

Energy of the electrons in the orbit is quantised

The electron in the orbit nearest the nucleus has the lowest energy

Electrons revolve in different orbits around the nucleus

The position and the velocity of the electrons cannot be determined simultaneously

8. The wavelength associated with a ball of mass 100g moving with a speed of 10³cm/sec (h= 6.6 m 10^-34J/s) is:-

6.6 × 1032 cm

6.6 × 1027 cm

6.6 × 10-27 cm

6.6 × 10-32 cm

9. The wavelength of spectral lines emitted is inversely proportional to?

Velocity

Energy

Quantum number

Radius

10. The wave number which corresponds to electromagnetic radiation of wavelength 500 nm is equal to

5×10-11 cm-1

2×104 cm-1

5×10-5 cm-1

2×10-9 sec-1

11. In an atom, for how many electrons, the quantum numbers will be, n=3, l=2 , m= +2 , s= +1/2

18

6

24

1

12. Assertion- The ground state configuration of Cr is 3d⁵4s¹ Reason- A set of exactly half filled orbitals containing parallel spin arrangement provide extra stability. Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D

13. Which of the following is represented by the configuration [Kr] 5s²

Ca

Sr

Ba

Ra

14. Electronic configuration given below has violated

Hund's rule

Paul's principle

Aufbau's principle

N+l rule

15. The De-broglie wavelength of an electron is 66 nm. The velocity of the electron is (h=6.6 m 10^-34kg m²s^-1m=9.0 m 10^-31kg)

1.84 × 10-14 m s-1

1.1 × 104 m s-1

5.4 × 103 m s-1

1.1 × 103 m s-1

16. The electronic transition from n=2 to n=1 will produce shortest wavelength in (where n = principle quantum state)

Li+2

He+

H

H+

17. Heisenberg Uncertainty principle is not valid for

Moving electron

Motor car

Stationary particles

2 & 3 both

18. Assertion- No teo electrons in an atom can have the same values of four quantum numbers. Reason- No two electrons in an atom can be simultaneously in the same shell, same Subshell, same orbitals and have same spin. Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D

19. The excitation energy of a hydrogen atom from its ground state to it's third excited state is

12.75 eV

0.85 eV

10.2 eV

12.1 eV

20. Assertion- An orbital cannot have more than two electrons Reason- The two electrons with opposite spin in an orbital create opposite magnetic field. Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D

21. Angular momentum for P-shell electron-

3h/π

Zero

√2h/2π

None

22. Assertion- In Rutherford's gold foil experiment, a very few alpha particles are deflected back. Assertion- Nucleus present inside the atom is heavy. Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D

23. Assertion- The configuration of B atom cannotbe 1s² 2s³ Reason- Hund's rule demands that the configuration should display maximum multiplicity. Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D

24. Assertion- Bohr model fails in case of multielectron species. Reason- It does not mention electron-electron interaction. Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D

25. The quantum numbers +1/2 and -1/2 for the electron spin represent?

Rotation of electron in clockwise and anticlockwise direction respectively.

Rotation of electron in anticlockwise and clockwise direction respectively.

Magnetic moment of the electron pointing up and down respectively

Two quantum mechanical spin states which have no classical analogue.

26. Which of the following is correctly matched

Isotopes 20Ca40 19K40

Isotones Si30 P31 S32

Isobars O16 O17 O18

Isoelectronic N-3 O-2 CrCr+3

27. Assertion- p- orbital has dumb bell shape. Reason- Electrons present in p-orbital can have three values for 'm' - 0, +1 , -1 Choose the answers appropriately. A: If both Assertion and Reason are True and Reason is the correct explanation of Assertion. B : If both Assertion and Reason are True but Reason is the wrong explanation of Assertion. C : If Assertion is True but Reason is False. D : If both Assertion and Reason are False.

A

B

C

D