Structure of Atoms MCQ's

Structure of Atom

Multiple Choice Questions

  

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1. A metal surface is exposed to solar radiations
   1.   The emitted electrons have energy less than a maximum value of energy depending upon the frequency of the incident radiation.
   2.   The emitted electrons have energy less than a maximum value of energy depending upon the intensity of the incident radiation.
   3.   The emitted electrons have zero energy.
   4.   The emitted electrons have energy equal to energy of photons of incident light.
2. The series of the lines present in the visible region of the hydrogen spectrum is
   1.   Lyman
   2.   Balmer
   3.   Paschen
   4.   Brackett
3. The line spectrum of He⁺ ion will resemble that of
   1.   Li+ ion
   2.   Helium atom
   3.   Lithium atom
   4.   Hydrogen atom
4. In photoelectric effect, the kinetic energy of the photoelectrons increases linearly with the
   1.   wavelength of incident light
   2.   velocity of incident light
   3.   frequency of incident light
   4.   atomic mass of the element.
5. Which of the following transition will have minimum wavelength?
   1.   n₄ -> n₁
   2.   n₂ -> n₁
   3.   n₄ -> n₂
   4.   n₃ -> n₁
6. According to Bohr’s theory, the angular momentum of an electron in 5^th orbit is
   1.   10 h/2Л
   2.   2.5 h/2Л
   3.   25 h/2Л
   4.   1.0 h/2Л
7. Principal, azimuthal and magnetic quantum numbers are respectively related to
   1.   Size, orientation and shape
   2.   Shape, size and orientation
   3.   Size, shape and orientation
   4.   None of the above
8. _____ states that, in an atom or molecule, no two electrons can have the same quantum numbers.
   1.   Aufbau Principle
   2.   Pauli Exclusion Principle
   3.   Hund’s rule of maximum multiplicity
   4.   (n+l) rule
9. _____ states that pairing of electrons in the orbitals belonging to the same subshell (p, d or f) does not take place until each orbital belonging to that subshell has got one electron each i.e. it is singly filled.
   1.   Aufbau Principle
   2.   Pauli Exclusion Principle
   3.   Hund’s rule of maximum multiplicity
   4.   (n+l) rule
10. ______ states that in the ground state of atoms, the orbitals are filled in order of their increasing energies.
    1.   Aufbau Principle
    2.   Pauli Exclusion Principle
    3.   Hund’s rule of maximum multiplicity
    4.   (n+l) rule
11. How many unpaired electrons are present in Fe
    1.   2
    2.   3
    3.   4
    4.   No unpaired electron
12. The radius of the first Bohr orbit of hydrogen atom is 0.59Å. The radius of the orbit of He⁺ will be
    1.   8.46 Å
    2.   1.59 Å
    3.   0.705 Å
    4.   2.38 Å
13. When the electron of a hydrogen atom jumps from n = 4 to n = 1 state, the number of spectral lines emitted is
    1.   15
    2.   6
    3.   3
    4.   9
14. The number of nodal planes ‘5d’ orbital has, is
    1.   zero
    2.   one
    3.   two
    4.   three
15. The number of radial nodes in 3s and 2p respectively are
    1.   2 and 0
    2.   1 and 2
    3.   0 and 2
    4.   2 and 1
16. A d- subshell can accommodate upto
    1.   six electrons
    2.   five electrons with parallel spin
    3.   ten electrons
    4.   five electrons with opposite spin
17. A p-orbital can accommodate upto
    1.   four electrons
    2.   six electrons
    3.   two electrons with opposite spin
    4.   two electrons with parallel spin
18. The number of 2p electrons having spin quantum number s = - ½ are
    1.   6
    2.   0
    3.   2
    4.   3
19. Which of the following statement about the electron is incorrect?
    1.   It is negatively charged particle.
    2.   It is a basic constituent of all atoms.
    3.   The mass of electron is equal to the mass of neutron.
    4.   It is a constituent of cathode rays.
20. Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons?
    1.   Heisenberg’s uncertainty principle
    2.   Pauli’s exclusion principle
    3.   Hund’s rule of maximum multiplicity
    4.   Aufbau principle
21. The shortest wavelength in hydrogen spectrum of Lyman series when R_H = 109678 cm^-1 is
    1.   100.27 nm
    2.   121.567 nm
    3.   112.73 nm
    4.   91.17 nm
22. The pair of ions having same electronic configuration is …….
    1.   Cr³⁺, Fe³⁺
    2.   Fe³⁺, Mn²⁺
    3.   Fe³⁺, Co³⁺
    4.   Sc³⁺, Cr³⁺
23. Total number of orbitals associated with third shell will be…….
    1.   2
    2.   3
    3.   4
    4.   9
24. Which of the following statements concerning the quantum numbers are correct?
    1.   Angular quantum numbers determines the three dimensional shape of the orbital.
    2.   The principal quantum number determines the orientation and energy of the orbital.
    3.   Magnetic quantum number determines the size of the orbital.
    4.   Spin quantum number determines the energy of the shell.
25. If a species has 16 protons, 18 electrons and 16 neutrons, find the species and its charge
    1.   S^-
    2.   Si²⁺
    3.   P^3-
    4.   S^2-
26. What will be the maximum number of electrons in a shell with (n=6)
    1.   72
    2.   36
    3.   32
       32
       34
    4.   34
27. A 600 W mercury lamp emits monochromatic radiation of wavelength 313.3 nm. How many photons are emitted from the lamp per second?
    1.   1 x 10¹⁹
    2.   1 x 10²⁰
    3.   1 x 10²¹
    4.   1 x 10²²
28. The wavelength of the electron emitted, when in a hydrogen atom, electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097 x 10⁷ m^-)
    1.   91 nm
    2.   9.1 x 10^-8 nm
    3.   192 nm
    4.   406 nm
29. Which of the following statements is incorrect? An atomic orbital
    1.   is a single electron wave function
    2.   describes trajectory of electron in an atom
    3.   defines distribution of electron density in space
    4.   can be represented by boundary surface diagrams.
30. Which of the following is not permissible arrangement of electrons in an atom?
    1.   n = 5, l = 3, m = 0, s = + ½
    2.   n = 3, l = 2, m = - 2, s = - ½
    3.   n = 4, l = 0, n = 0, s = - ½
    4.   n = 3, l = 2, m = -3, s = - ½
31. For principal quantum number n = 4, the total number of orbitals having l = 3 is
    1.   3
    2.   7
    3.   5
    4.   9
32. The set of quantum numbers for the outermost electron for copper in its ground state is …..
    1.   4, 1, 1, +1/2
    2.   3, 2, ,2 +1/2
    3.   4, 0, 0, +1/2
    4.   4, 2, 2, +1/2
33. Which one of the following statements is wrong about photon?
    1.   Photon’s energy is hν
    2.   Photon’s rest mass is zero
    3.   Momentum of photon is hν/c
    4.   Photon exerts no pressure
34. Amplification of electromagnetic waves by stimulated emission of radiation produces
    1.   X-rays
    2.   Gamma-rays
    3.   Laser
    4.   Radiowaves
35. Which of the following orbitals will have zero probability of finding the electron in the yz plane?
    1.   p_x
    2.   p_y
    3.   p_z
    4.   d_xy
36. Arrange in decreasing order, the energy of 2s orbital in the following atoms
    H, Li, Na, K
    1.   E_2s (H) > E_2s (Li) > E_2s (Na) > E_2s (K)
    2.   E_2s (H) > E_2s (Na) > E_2s (Li) > E_2s (K)
    3.   E_2s (H) > E_2s (Na) = E_2s (K) > E_2s (Li)
    4.   E_2s (K) > E_2s (Na) > E_2s (Li) > E_2s (H)
37. Using s, p ,d notations, describe the orbitals with the following quantum numbers
    n=4, l=1
    1.   4s
    2.   4p
    3.   4d
    4.   4f
38. When the frequency of the incident radiation on a metallic plate is doubled, KE of the photoelectrons will be
    1.   doubled
    2.   halved
    3.   more than doubled
    4.   increases but less than doubled
39. Maximum number of electrons in a subshell of an atom is determined by the following
    1.   2 l + 1
    2.   4 l – 2
    3.   2 n2
    4.   4 l + 2
40. What is the atomic number of elements whose outermost electrons are represented by 3d⁶
    1.   24
    2.   16
    3.   26
    4.   28

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