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## Structure of Atom MCQs

**1. Thomson discovered that every substance in this universe is made up of ________ from his experiments.**

a) neutrons

b) protons

c) electrons

d) mass

**Answer: **electrons

**2. When cathode rays strike zinc sulfide coating, what did it create?**

a) bright spot

b) blue light

c) uv rays

d) white light

**Answer: **bright spot

**3. ___________ is the lightest and smallest particles that’s obtained from hydrogen(that is a positive ion).**

a) Electron

b) Proton

c) Neutron

d) Particle

**Answer: **Proton

**4. What’s the mass of neutron in terms of electrons mass?**

a) 1838 times of electron’s mass

b) 1/1838 times of electron’s mass

c) 1832 times of electron’s mass

d) 1/1832 times of electron’s mass

**Answer: **1838 times of electron’s mass

**5. Neutrally charged particles are protons.**

a) True

b) False

**Answer: **False

**6. Which of the following may be an incorrect statement regarding cathode ray discharge tube?**

a) Presence of negative charge in cathode rays

b) The magnetic field deflects these rays

c) It needs high voltage

d) Protons are present in cathode rays

**Answer: **Protons are present in cathode rays

**7. Which of the following condition is suitable for cathode ray discharge tube?**

a) Low pressure, high voltage

b) Low pressure, low voltage

c) High pressure, low voltage

d) High pressure, high voltage

**Answer: **Low pressure, high voltage

**8. If the number of protons and neutrons of an element is 13 and 14 respectively, then what’s the atomic number(Z) and mass number(A)?**

a) 13, 13

b) 13, 27

c) 14, 13

d) 27, 14

**Answer: **13, 27

**9. Which of the following is not an isotope of hydrogen?**

a) protium

b) deuterium

c) tritium

d) helium

**Answer: **helium

**10. Chemical properties of an atom are dependent on a number of electrons in that particular atom.**

a) True

b) False

**Answer: **True

**11. Find out the number of neutrons, protons, and electrons of 17Cl37 respectively.**

a) 20, 20, 17

b) 17, 17, 20

c) 20, 17, 17

d) 17, 17, 17

**Answer: **20, 17, 17

**12. ****Gravitational force = Gm**_{1}**m**_{2}**/r**^{2}**.**

_{1}

_{2}

^{2}

a) True

b) False

**Answer: **True

**13. ****Pick out the isobar of **_{18}**Ar**^{40}**.**

_{18}

^{40}

a) _{12}Mg^{24}

b) _{26}Fe^{58}

c) _{19}K^{40}

d) _{28}Ni^{64}

**Answer: **_{19}K^{40}

**14****. What is t****he absolute charge of a proton?**

a) +1.602176×10^{-27}

b) –1.602176×10^{-19}

c) +1.602176×10^{-19}

d) –1.602176×10^{-27}

**Answer: **–1.602176×10^{-19}

**15. Which of the following models are not the same as Thomson Model of Atom?**

a) plum pudding model

b) watermelon model

c) raisin pudding model

d) nuclear model

**Answer: **nuclear model

**15. ________ frequency, is the minimum frequency required to eject an electron when photons hit the metal surface.**

a) Required

b) Activated

c) Threshold

d) Limiting

**Answer: **Threshold

**16. A metal’s work function is 3.8KJ. Photons strike metal’s surface with an energy of 5.2 KJ. what’s the kinetic energy of the emitted electrons?**

a) 3.8 KJ

b) 5.2 KJ

c) 9 KJ

d) 1.4 KJ

**Answer: **1.4 KJ

**17. When an electron jumps from 3rd orbit to 2nd orbit, which series of spectral lines are obtained?**

a) Balmer

b) Lyman

c) Paschen

d) Brackett

**Answer: **Balmer

**18. ****Find out the wavenumber, when an electron jumps from 2**^{nd}** orbit to 1**^{st}**.**

^{nd}

^{st}

a) 82357.75 cm^{-1}

b) 105,677 cm^{-1}

c) 82257.75 cm^{-1}

d) 109,677 cm^{-1}

**Answer: **82257.75 cm^{-1}

**19. The ultraviolet spectral region is obtained in Balmer series.**

a) True

b) False

**Answer: **False

**20. What’s the wavelength for the visible region in electromagnetic radiation?**

a) 400 – 750 nm

b) 400 – 750 mm

c) 400 – 750 μm

d) 400 – 750 pm

**Answer: **400 – 750 nm

**21. Calculate the frequency of the wave whose wavelength is 10nm.**

a) 2 Hz

b) 3 Hz

c) 1 Hz

d) 4 Hz

**Answer: **3 Hz

**22. ****What is ****the wavenumber of violet color?**

a) 25 x 10^{3} mm^{-1}

b) 25 x 10^{3} m^{-1}

c) 25 x 10^{3} cm^{-1}

d) 25 x 10^{3} nm^{-1}

**Answer: **25 x 10^{3} cm^{-1}

**23. Bohr’s model couldn’t explain Zeeman and stark effect.**

a) False

b) True

**Answer: **True

**24. Bohr’s model could not explain the ability of atoms to form molecules by ______**

a) Attraction

b) Physical bonds

c) Chemical bonds

d) Polarity

**Answer: **Chemical bonds

**25. Calculate the wavelength of a photon that traveled from 5th orbit to 2nd orbit.**

a) 434 nm

b) 456 nm

c) 863 nm

d) 268 nm

**Answer: **434 nm

**26. The energy of a hydrogen atom is positive.**

a) True

b) False

**Answer: **False

**27. ****Which of the following is ****the value for Rydberg constant?**

a) 2.95 x 10^{-18} J

b) -2.95 x 10^{-18} J

c) -2.18 x 10^{-18} J

d) 2.18 x 10^{-18} J

**Answer: **-2.18 x 10^{-18} J

**28. Iω = _________**

a) m_{e}v^{2}r

b) m_{e}vr^{2}

c) m_{e}r

d) m_{e}vr

**Answer: **m_{e}vr

**29. Angular momentum of an electron is quantized.**

a) True

b) False

**Answer: **True

**30. ****The energy of 1**^{st}** orbi****t in a hydrogen atom __________**

^{st}

a) 3.18×10^{–12} J

b) –2.18×10^{–18} J

c) –3.18×10^{–18} J

d) 2.18×10^{–18} J

**Answer: **–2.18×10^{–18} J

**31. As per Heisenberg’s principle of uncertainty, the relation between relative momentum and relative position is __________**

a) independent

b) equal

c) directly proportional

d) inversely proportional

**Answer: **inversely proportional

**32. Δx. Δp ≥ h/4π.**

a) True

b) False

**Answer: **True

**33. ****An object has a mass of 6 kg and velocity of 10 m/s. The speed is measured with 5% a****ccuracy, then find out Δx in m.**

a) 0.12676 x 10^{-34}

b) 0.1566 x 10^{-34}

c) 0.176 x 10^{-34}

d) 0.276 x 10^{-34}

**Answer: **0.176 x 10^{-34}

**34. ****If the kinetic energy of an electron ****is 5J. Find out its wavelength.**

a) 0.313 x 10^{15} m/s

b) 3.013 x 10^{15} m/s

c) 3.310 x 10^{15} m/s

d) 3.313 x 10^{15} m/s

**Answer: **3.313 x 10^{15} m/s

**35. If the uncertainties in position and momentum are equal, then the uncertainty in position is given by ____**

a) √h/4π

b) √h4π

c) √h/4

d) √h/π

**Answer: **√h/4π

**36. ****The uncertainty of a ball is given by 0.5A°. Then calcula****te the uncertainty in momentum.**

a) 2.055 x 10^{-24} kgm/s

b) 1.015 x 10^{-24} kgm/s

c) 1.055 x 10^{-24} kgm/s

d) 1.095 x 10^{-24} kgm/s

**Answer: **1.055 x 10^{-24} kgm/s

**37. ****Mass of a photon is given by 3.313 x 10**^{-34}** kg. Find it’s wavelength.**

^{-34}

a) 0.67A°

b) 0.67nm

c) 0.37A°

d) 1.67A°

**Answer: **0.67A°

**38. ****A ball of mass 0.5kg is moving with velocity 6.626 m/s. What****’s the wavelength of that ball?**

a) 1 x 10^{-34} m

b) 2 x 10^{-34} m

c) 2 x 10^{-32} m

d) 2 x 10^{-3} m

**Answer: **2 x 10^{-34} m

**39. How many electrons can exist with the principal quantum number’s value as 4?**

a) 16

b) 4

c) 32

d) 12

**Answer: **32

**40. No two electrons have the same set of all four quantum numbers.**

a) True

b) False

**Answer: **True

**41. According to the Aufbau’s principle, which of the following orbital should be filled first?**

a) 5d

b) 4p

c) 3p

d) 2s

**Answer: **2s

**42. Which of the following set of quantum numbers is not valid?**

a) n = 5, l = 2, m = 0, s = 1/2

b) n = 1, l = 2, m = 0, s = 1/2

c) n = 5, l = 3, m = 2, s = 1/2

d) n = 5, l = 2, m = 0, s = -1/2

**Answer: **n = 1, l = 2, m = 0, s = 1/2

**43. Total number of nodes for 3d orbital is ________**

a) 3

b) 2

c) 1

d) 0

**Answer: **2

**44. What is the magnetic quantum number of the orbital 2pz?**

a) 1

b) ±1

c) -1

d) 0

**Answer: **0

**45. What is the shape the orbital, whose “l” is 1?**

a) Spherical

b) Dumbbell

c) Double dumbbell

d) Complex

**Answer: **Dumbbell

**46. The principal quantum number describes ____**

a) energy and size of the orbit

b) the shape of the orbital

c) spatial orientation of the orbital

d) the spin of the electron

**Answer: **energy and size of the orbit