Atomic Structure PYQs Set 1 (PDF)

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Mere Teacher · Previous Year Questions NEET Chemistry · Atomic Structure · Set 1 (Q1-30)
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1. $Uncertainity in the position of an electron (mass = 9.1 \times 1 0^{-31} Kg) moving with a velocity 300 m. se c^{-1}, Accurate up to 0.001%, will be: (h = 6.63 \times 1 0^{-34} J-s)$ (1) $19.2 \times 1 0^{-2} m$ (2) $5.76 \times 1 0^{-2} m$ (3) $1.92 \times 1 0^{-2} m$ (4) $3.84 \times 1 0^{-2} m$ 2. $For emission line of atomic hydrogen from n_{i} = 8 to n_{f} = n, the plot of wave number (v) against (\frac{1}{n ^{2}}) will be (The Rydberg constant, R_{H} is in wave number unit)$ (1) $Linear with intercept - R_{H}$ (2) $Non linear$ (3) $Linear with slope R_{H}$ (4) $Linear with slope - R_{H}$ 3. $Which of the following statements regarding the energy of the stationary state is true in the following one - electron systems?$ (1) $+ 2.18 \times 10^{- 18} J for second orbit of He+ion$ (2) $- 2.18 \times 10^{- 18} J for third orbit of Li^{2 +} ion$ (3) $- 1.09 \times 10^{- 18} J for second orbit of H atom.$ (4) $+ 8.72 \times 10^{- 18} J for first orbit of He+ion$ 4. $When the azimuthal quantum number has the value of 2 , the number of orbitals possible are$ (1) $3$ (2) $0$ (3) $7$ (4) $5$ 5. $What is the maximum number of orbitals that can be identified with the following quantum numbers? n = 3, l = 1, m_{l} = 0$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 6. $The product of uncertainty in the position and uncertainty in velocity of a particle is 5.79 \times 10^{- 5} m^{2} s^{- 1} . If uncertainty in the position is 1 nm, what is the uncertainty in the measurement of its velocity in ms^{- 1} ?$ (1) $5.79 \times 10^{7}$ (2) $5.79 \times 10^{5}$ (3) $5.79 \times 10^{- 5}$ (4) $5.79 \times 10^{4}$ 7. $What is the wave number of photon emitted during transition from orbit, n = 4 to n = 2 in hydrogen atom (R_{H} = 109677 cm^{- 1}) ?$ (1) $20564.44 cm^{- 1}$ (2) $15354.78 cm^{- 1}$ (3) $23032.17 cm^{- 1}$ (4) $25225.7 cm^{- 1}$ 8. $For electrons in ' 2 s' and ' 2 p' orbitals, the orbital angular momentum values, respectively are:$ (1) $0 and 6 \frac{h}{2 π}$ (2) $0 and 2 \frac{h}{2 π}$ (3) $2 \frac{h}{2 π} and 0$ (4) $\frac{h}{2 π} and 2 \frac{h}{2 π}$ 9. $How many electrons can fit in the orbital for which n = 3 and l = 1 ?$ (1) $2$ (2) $6$ (3) $10$ (4) $14$ 10. $The de Broglie wavelength of an electron travelling with 20 % of velocity of light is (h = 6.626 \times 10^{- 34} Js; m_{e} = 9.1 \times 10^{- 31} kg)$ (1) $2.4 \times 10^{- 11} m$ (2) $1.2 \times 10^{- 11} m$ (3) $3.6 \times 10^{- 11} m$ (4) $4.8 \times 10^{- 11} m$ 11. $In the sixth period, the orbitals that are filled are$ (1) $6 s, 4 f, 5 d, 6 p$ (2) $6 s, 5 d, 5 f, 6 p$ (3) $6 s, 6 p, 6 d, 6 f$ (4) $6 s, 5 f, 6 d, 6 p$ 12. $If the energies of the two photons are in the ratio of 3 : 2, their wavelengths will be the ratio of$ (1) $9 : 4$ (2) $2 : 3$ (3) $1 : 2$ (4) $3 : 2$ 13. $The atomic number of Ni and Cu are 28 and 29 respectively. The electronic configuration 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} represents$ (1) $Cu^{+}$ (2) $Cu^{2 +}$ (3) $Ni^{2 +}$ (4) $Ni$ 14. $A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of \frac{h}{λ} (where λ is wavelength associated with electron wave) is given by$ (1) $2meV$ (2) $meV$ (3) $2 meV$ (4) $meV$ 15. $Given below are two statements: Statement (I): A spectral line will be observed for a 2 p_{x} \to 2 p_{y} transition. Statement (II): 2 P_{x} and 2 p_{y} are degenerate orbitals. choose the correct answer from the options given below:$ (1) $Both Statement I and Statement II are true$ (2) $Statement I is false but Statement II is true$ (3) $Both Statement I and Statement II are false$ (4) $Statement I is true but Statement II is false$ 16. $Given below are two statements Statement I : According to Bohr's model of hydrogen atom, the angular momentum of an electron in a given stationary state is quantised. Statement II: The concept of electron in Bohr's orbit, violates the Heisenberg uncertainty principle. In the light of the above statements, choose the most appropriate answer from the options given below$ (1) $Statement I is incorrect but Statement II is correct$ (2) $Both Statement I and Statement II are correct$ (3) $Both Statement I and Statement II are incorrect$ (4) $Statement I is correct but Statement II is incorrect$ 17. $Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect ? (The Bohr radius is represented by a_{0}).$ (1) $The probability density of finding the electron is maximum at the nucleus.$ (2) $The electron can be found at a distance 2 a_{0} from the nucleus$ (3) $The magnitude of potential energy is double that of its kinetic energy on an average.$ (4) $The total energy of the electron is maximum when it is at a distance from the nucleus.$ 18. $The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097 \times 1 0^{7} m^{-1})$ (1) $91 nm$ (2) $192 nm$ (3) $406$ (4) $9.1 \times 1 0^{- 6} nm$ 19. $Arrange the following orbitals in decreasing order of energy? (A)n=3, l = 0, m = 0 (B) n = 4,1 = 0, m = 0 (C)n = 3, l=1, m=0 (D)n = 3,l = 2,m=1 The correct option for the order is :$ (1) $B>D>C>A$ (2) $D>B>C>A$ (3) $A>C>B>D$ (4) $D>B>A>C$ 20. $The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is [a_{0} is Bohr radius]:$ (1) $\frac{h ^{2}}{4 π ^{2} m a _{0}^{2}}$ (2) $\frac{h ^{2}}{16 π ^{2} m a _{0}^{2}}$ (3) $\frac{h ^{2}}{32 π ^{2} m a _{0}^{2}}$ (4) $\frac{h ^{2}}{64 π ^{2} m a _{0}^{2}}$ 21. $The electronic configuration of Pt (atomic number 78) is:$ (1) $[Xe] 4 f^{14} 5 d^{9} 6 s^{1}$ (2) $[Kr] 4 f^{14} 5 d^{10}$ (3) $[Xe] 4 f^{l 4} 5 d^{10}$ (4) $[Xe] 4 f^{14} 5 d^{8} 6 s^{2}$ 22. $The energy of second orbit of hydrogen atom is - 5.45 \times 10^{- 19} J . What is the energy of first orbit of Li^{2 +} ion (in J)?$ (1) $- 1.962 \times 10^{- 18}$ (2) $- 1.962 \times 10^{- 17}$ (3) $- 3.924 \times 10^{- 17}$ (4) $- 3.924 \times 10^{- 18}$ 23. $On the basis of Bohr's model, the radius of the 3rd orbit is$ (1) $equal to the radius of 1 st orbit$ (2) $3 times the radius of 1 st orbit$ (3) $5 times the radius of 1 st orbit$ (4) $9 times the radius of 1 st orbit$ 24. $Radius of the first excited state of Helium ion is given as : a_{0} \to radius of first stationary state of hydrogen atom.$ (1) $r = 4 a_{0}$ (2) $r = 2 a_{0}$ (3) $r = \frac{a _{0}}{2}$ (4) $r = \frac{a _{0}}{4}$ 25. $The radius of third orbit of hydrogen atom is Rpm . The radius of second orbit of He^{+} ion (in pm is)$ (1) $\frac{4}{3} R$ (2) $\frac{3}{4} R$ (3) $\frac{9}{2} R$ (4) $\frac{2}{9} R$ 26. $If the radius of the first orbit of hydrogen atom is a_{0}, then de Broglie's wavelength of electron in 3^{r d} orbit is$ (1) $\frac{π a _{0}}{6}$ (2) $\frac{π a _{0}}{3}$ (3) $6 π a_{0}$ (4) $3 π a_{0}$ 27. $Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 \times 1 0^{3} m s^{-1} (Mass of proton = 1.67 \times 1 0^{-27} kg and h = 6.63 \times 1 0^{-34} Js):$ (1) $0.40 nm$ (2) $2.5 nm$ (3) $14.0 nm$ (4) $0.032 nm$ 28. $Maximum number of electrons that can be accommodated in shell with n = 4 are:$ (1) $16$ (2) $32$ (3) $50$ (4) $72$ 29. $Ionization energy of gaseous Na atom is 495.5 kJ m o l^{-1} . The lowest possible frequency of light that ionizes a sodium atom is (h = 6.626 \times 1 0^{-34} Js, N_{A} = 6.022 \times 1 0^{23} mol^{-1})$ (1) $7.50 \times 1 0^{4} s^{-1}$ (2) $4.76 \times 1 0^{14} s^{-1}$ (3) $3.15 \times 1 0^{15} s^{-1}$ (4) $1.24 \times 1 0^{15} s^{-1}$ 30. $Which of the following sets of quantum numbers is correct for an electron in 4 f orbital?$ (1) $n = 3, l = 2, m_{1} = - 2, m_{s} = + 1/2$ (2) $n = 4, l = 3, m_{1} = + 1, m_{s} = + 1/2$ (3) $n = 4, l = 3, m_{1} = + 4, m_{s} = + 1/2$ (4) $n = 4, l = 4, m_{1} = + 4, m_{s} = - 1/2$