Atomic Structure PYQs Set 7 (PDF)

Set 7 of 12 · Questions 181-210 of 359

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Mere Teacher · Previous Year Questions NEET Chemistry · Atomic Structure · Set 7 (Q181-210)
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181. $The electrons identified by quantum numbers n and λ: (A) n = 4, λ = 1 (B) n = 4, λ = 0 (C) n = 3, λ = 2 (D) n = 3, λ = 1 can be placed in order of increasing energy as:$ (1) $(C) < (D) < (B) < (A)$ (2) $(D) < (B) < (C) < (A)$ (3) $(B) < (D) < (A) < (C)$ (4) $(A) < (C) < (B) < (D)$ 182. $Among the elements from atomic number 1 to 36 , the number of elements which have an unpaired electron in their s -subshell is$ (1) $4$ (2) $7$ (3) $6$ (4) $9$ 183. $The energy (in eV) associated with the electron in the 1st orbit of Li^{2 +} is$ (1) $-122.4$ (2) $-61.15$ (3) $-30.5$ (4) $-244.6$ 184. $A light of frequency 1.6 \times 10^{16} Hz when falls on a metal plate emits electrons that have double the kinetic energy compared to the kinetic energy of emitted electrons when frequency of 1.0 \times 10^{16} Hz falls on the same plate. The threshold frequency (v_{0}) of the metal in Hz is$ (1) $1 \times 10^{15}$ (2) $4 \times 10^{15}$ (3) $3 \times 10^{15}$ (4) $4 \times 10^{13}$ 185. $The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19) are$ (1) $n = 4, l = 2, m = - 1, s = + \frac{1}{2}$ (2) $n = 4, l = 0, m = 0, s = + \frac{1}{2}$ (3) $n = 3, l = 0, m = 1, s = + \frac{1}{2}$ (4) $n = 2, l = 0, m = 0, s = + \frac{1}{2}$ 186. $How many orbitals is/are possible with n = 3, l = 1 and m_{l} = - 1 value?$ (1) $2$ (2) $3$ (3) $5$ (4) $1$ 187. $The radius of the 2^{n d} orbit of L i^{2 +} is x. The expected radius of the 3^{r d} orbit of B e^{3}^ is$ (1) $\frac{9}{4} x$ (2) $\frac{4}{9} x$ (3) $\frac{27}{16} x$ (4) $\frac{16}{27} x$ 188. $For azimuthal quantum number l = 3, the maximum number of electrons will be$ (1) $2$ (2) $6$ (3) $0$ (4) $14$ 189. $If a suitable photon is employed to locate an electron (mass (= 9.11 \times 10^{- 31} kg) in an atom within a distance of 10.98 nm, the uncertainty involved in the measurement of its velocity in ms^{- 1} is$ (1) $\frac{1.6565 \times 10 ^{6}}{π}$ (2) $\frac{1.6565 \times 10 ^{4}}{π}$ (3) $1.6565\times 1 0^{- 8} π$ (4) $\frac{1.6565 \times 10 ^{8}}{π}$ 190. $If Δ x is the uncertainity in position and Δ v is the uncertainity in velocity of a particle are equal, the correct expression for uncertainity in momentum for the same particle is$ (1) $\frac{1}{4} \frac{mh}{π}$ (2) $\frac{1}{3} \frac{mh}{2 π}$ (3) $\frac{1}{2} \frac{mh}{π}$ (4) $\frac{1}{2} \frac{h}{mπ}$ 191. $The number of s-electrons present in an ion with 55 protons in its unipositive state is$ (1) $8$ (2) $9$ (3) $12$ (4) $10$ 192. $Which of the following is/are not correct with respect to energy of atomic orbitals of hydrogen atom? (A) 1 s < 2 p < 3 d < 4 s (B) 1 s < 2 s = 2 p < 3 s = 3 p (C) 1 s < 2 s < 2 p < 3 s < 3 p (D) 1 s < 2 s < 4 s < 3 d Choose the correct answer from the options given below :$ (1) $(A) and (C) only$ (2) $(B) and (D) only$ (3) $(C) and (D) only$ (4) $(A) and (B) only$ 193. $What is the work function of the metal if the light of wavelength 4000Å generates photoelectrons of velocity 6\times 1 0^{5} m s^{-1} from it ? (Mass of electron = 9 \times 1 0^{-31} kg, Velocity of light = 3\times 1 0^{8} m s^{-1}, Plank's constant = 6.626 \times 1 0^{-34} Js, Charge of electron = 1.6 \times 1 0^{-19} J e V^{-1})$ (1) $3.1 eV$ (2) $0.9 eV$ (3) $4.0 eV$ (4) $2.1 eV$ 194. $Energy of H-atom in the ground state is -13.6 eV, hence energy in the second excited state is :$ (1) $- 6.8 eV$ (2) $- 3.4 eV$ (3) $- 1.51 eV$ (4) $- 4.53 eV$ 195. $The figure that is not a direct manifestation of the quantum nature of atoms is$ (1) (2) (3) (4) 196. $Match the following pairs. Species Number of electrons (A) O^{2 -} (i) 18 (B) Li^{2 +} (ii) 2 (C) He (iii) 10 (D) Ca^{++} (iv) 1$ (1) $(A) - (i), (B) - (ii), (C) - (iv), (D) - (iii)$ (2) $(A) - (ii), (B) - (iii), (C) - (i), (D) - (iv)$ (3) $(A) - (iii), (B) - (iv), (C) - (ii), (D) - (i)$ (4) $(A) - (iv), (B) - (i), (C) - (iii), (D) - (ii)$ 197. $Impossible orbital among the following is$ (1) $2 s$ (2) $3 f$ (3) $2 p$ (4) $4 d$ 198. $The orbit having Bohr radius equal to 1^{s t} Bohr orbit of H-atom is:$ (1) $n = 2 of H e^{+}$ (2) $n = 2 of B^{+ 4}$ (3) $n = 3 of L i^{+ 2}$ (4) $n = 2 of B e^{+ 3}$ 199. $The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about 9. The spectral series are:$ (1) $Lyman and Paschen$ (2) $Balmer and Brackett$ (3) $Brackett and Pfund$ (4) $Paschen and Pfund$ 200. $If λ_{0} and λ be the threshold wavelength and wavelength of incident light, the velocity of photoelectron ejected from the metal surface is :$ (1) $\frac{2 h}{m} (λ_{0} - λ)$ (2) $\frac{2 hc}{m} (λ_{0} - λ)$ (3) $\frac{2 hc}{m} (\frac{λ _{0} - λ}{λ λ _{0}})$ (4) $\frac{2 h}{m} (\frac{1}{λ _{0}} - \frac{1}{λ})$ 201. $Given,(A) n = 5, m_{l} = - 1 (B) n = 3, l = 2, m_{l} = - 1, m_{s} = + \frac{1}{2} The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are:$ (1) $8 and 1$ (2) $2 and 4$ (3) $26 and 1$ (4) $4 and 1$ 202. $If radius of second Bohr orbit of the He^{+} ion is 105.8 pm , what is the radius of third Bohr orbit of Li^{2 +} ion?$ (1) $15.87 pm$ (2) $1.587 pm$ (3) $158.7Å$ (4) $158.7 pm$ 203. $The de Broglie wavelength of a particle with mass 1 g and velocity 100 m / s is$ (1) $6. 63 \times 1 0^{- 35} m$ (2) $6. 63 \times 1 0^{- 34} m$ (3) $6. 63 \times 1 0^{- 33} m$ (4) $6. 65 \times 1 0^{- 35} m$ 204. $The orientation of an atomic orbital is governed by$ (1) $principal quantum number$ (2) $azimuthal quantum number$ (3) $spin quantum number$ (4) $magnetic quantum number$ 205. $According to Bohr’s theory, the angular momentum to an electron in 5^{t h} orbit is :$ (1) $25 \frac{h}{π}$ (2) $1.0 \frac{h}{π}$ (3) $10 \frac{h}{π}$ (4) $2.5 \frac{h}{π}$ 206. $Calculate the wave number and frequency of orange radiation having wavelength 6300Å .$ (1) $1.587 \times 10^{8} m^{- 1}, 4.761 \times 10^{16} s^{- 1}$ (2) $1.587 \times 10^{4} m^{- 1}, 4.761 \times 10^{14} s^{- 1}$ (3) $1.587 \times 10^{6} m^{- 1}, 4.761 \times 10^{14} s^{- 1}$ (4) $1.587 \times 10^{6} m^{- 1}, 4.761 \times 10^{16} s^{- 1}$ 207. $The number of radial nodes, angular nodes of a 4 f - orbital are respectively$ (1) $0,3$ (2) $1,2$ (3) $2,1$ (4) $2,0$ 208. $The energy of an electron in first Bohr orbit of H-atom is -13.6 eV. The energy value of electron in the excited state of L i^{2 +} is :$ (1) $- 27.2 eV$ (2) $30.6 eV$ (3) $- 30.6 eV$ (4) $27.2 eV$ 209. $Maximum number of electrons possible with spin quantum number + \frac{1}{2} with principal quantum number n = 4 in an atom is$ (1) $16$ (2) $9$ (3) $4$ (4) $25$ 210. $In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with which the position of the electron can be located is (h = 6.6 \times 1 0^{-34} kg m^{2} s^{-1}, mass of electron, e_{m} = 9.1 \times 1 0^{-31} kg):$ (1) $5.10 \times 1 0^{-3} m$ (2) $1.92 \times 1 0^{-3} m$ (3) $3.83 \times 1 0^{-3} m$ (4) $1.52 \times 1 0^{-4} m$