Atomic Structure PYQs Set 5 (PDF)

Set 5 of 14 · Questions 121-150 of 415

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Atomic Structure · Set 5 (Q121-150)
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121. $The number of protons, neutrons and electrons in_{71}^{175} Lu, respectively are$ (1) $71, 104 and 71$ (2) $104, 71 and 71$ (3) $71, 71 and 104$ (4) $175, 104 and 71$ 122. $The pair, in which ions are isoelectronic with A 1^{3 +} is :-$ (1) $Br and B e^{2 +}$ (2) $C l^{-} and L i^{+}$ (3) $S^{2 -} and K^{+}$ (4) $O^{2 -} and M g^{2 +}$ 123. $The number of oribtals associated with quantum number n = 5, m_{s} = + \frac{1}{2}$ (1) $25$ (2) $30$ (3) $50$ (4) $35$ 124. $At temperatuere T, the average kinetic energy of any particle is \frac{3}{2} KT. The de Broglie wavelength follows the order:$ (1) $Visible photon > Thermal neutron > Thermal electron$ (2) $Thermal proton > Thermal electon > Visible photon$ (3) $Thermal proton > Visible photon > Thermal electron$ (4) $Visible photon > Thermal electron > Thermal neutron$ 125. $Which of the following postulate of Bohr's model of hydrogen atom is not in agreement with quantum mechanical model of an atom?$ (1) $The electron in a H atom's stationary state moves in a circle around the nucleus.$ (2) $An atom can take only certain distinct energies E_{1}, E_{2}, E_{3}, etc. These allowed states of constant energy are called the stationary states of atom.$ (3) $An atom in a stationary state does not emit electromagnetic radiation as long as it stays in the same state.$ (4) $When an electron makes a transition from a higher energy stationary state to a lower energy stationary state, then it emits a photon of light.$ 126. $Vijayawada FM radio station broadcasts at frequency of 103.4 MHz. The wavelength of the corresponding radio waves (in m) is$ (1) $2.90$ (2) $29.0$ (3) $9.20$ (4) $92.0$ 127. $Given below are two statements: Statement-I: The orbitals having same energy are called as degenerate orbitals. Statement-II: In hydrogen atom, 3 p and 3 d orbitals are not degenerate orbitals. In the light of the above statements, choose the most appropriate answer from the options given$ (1) $Statement-I is true but Statement-II is false$ (2) $Both Statement-I and Statement-II are true.$ (3) $Both Statement-I and Statement-II are false$ (4) $Statement-I is false but Statement-II is true$ 128. $B e^{2 +} is isoelectronic with which ofthe following ions?$ (1) $H^{+}$ (2) $L i^{+}$ (3) $N a^{+}$ (4) $M g^{2 +}$ 129. $The de-Broglie's wavelength of electron present in first Bohr orbit of 'H' atom is :$ (1) $0.529 Å$ (2) $2π \times 0.529 Å$ (3) $\frac{0.529}{2 π} Å$ (4) $4 \times 0.529 Å$ 130. $The correct set of four quantum numbers for outermost electron of potassium (Z = 19) is$ (1) $3, 1, 0, \frac{1}{2}$ (2) $4, 0, 0, \frac{1}{2}$ (3) $3, 0, 0, \frac{1}{2}$ (4) $4, 1, 0, \frac{1}{2}$ 131. $If two particles A and B are moving with the same velocity, but wavelength of A is found to be double than that of B . Which of the following statement is correct?$ (1) $Both A and B have same mass.$ (2) $Mass of A is half that of B .$ (3) $Mass of B is half that of A .$ (4) $Mass of B is one-fourth that of A .$ 132. $The number of angular nodes and radial nodes in 3s orbital are:$ (1) $1 and 0, respectively$ (2) $3 and 0, respectively$ (3) $0 and 1, respectively$ (4) $0 and 2, respectively$ 133. $If the de Broglie wavelength of the electron in n^{th} Bohr orbit in a hydrogenic atom is equal to 1.5 π a_{0} (a_{0} is Bohr radius), then the value of n/z is :$ (1) $0.40$ (2) $1.50$ (3) $1.0$ (4) $0.75$ 134. $The energies E_{1} and E_{2} of two radiations are 25 e V and 50 e V respectively. The relation between their wavelengths i.e., λ_{1} and λ_{2} will be$ (1) $λ_{1} = λ_{2}$ (2) $λ_{1} = 2 λ_{2}$ (3) $λ_{1} = 4 λ_{2}$ (4) $λ_{1} = \frac{1}{2} λ_{2}$ 135. $The total number of spectral lines observed when electron returns from the 6^{th} shell until the 2^{nd} shell in hydrogen atom is$ (1) $15$ (2) $10$ (3) $8$ (4) $2$ 136. $The radius of the second Bohr orbit, in terms of the Bohr radius, a_{0}, in L i^{2 +} is$ (1) $\frac{3 a _{0}}{4}$ (2) $\frac{4 a _{0}}{3}$ (3) $\frac{a _{0}}{3}$ (4) $\frac{16 a _{0}}{9}$ 137. $The orbital having two radial as well as two angular nodes is$ (1) $5d$ (2) $4f$ (3) $3p$ (4) $4d$ 138. $Which is the correct order of increasing energy of the listed orbitals in the atom of titanium? (At. no. Z = 22)$ (1) $4 s 3 s 3 p 3 d$ (2) $3 s 3 p 3 d 4 s$ (3) $3 s 3 p 4 s 3 d$ (4) $3 s 4 s 3 p 3 d$ 139. $The wavelength of photon ' A ' is 400 nm. The frequency of photon ' B ' is 10^{16} s^{- 1} . The wave number of photon ' C^{’} is 10^{4} cm^{- 1} . The correct order of energy of these photons is:$ (1) $C > B > A$ (2) $B > A > C$ (3) $A > B > C$ (4) $A > C > B$ 140. $Electronic configuration of calcium atom can be written as$ (1) $[Ne] 4 p^{2}$ (2) $[Ar] 4 s^{2}$ (3) $[Ne] 4 s^{2}$ (4) $[Kr] 4 p^{2}$ 141. $Which of the following electronic configuration would be associated with the highest magnetic moment?$ (1) $[Ar] 3 d^{7}$ (2) $[Ar] 3 d^{8}$ (3) $[Ar] 3 d^{3}$ (4) $[Ar] 3 d^{6}$ 142. $The approximate ratio of the speed of light in vacuum to that of an electron in the first Bohr orbit of hydrogen atom is$ (1) $100 : 1$ (2) $137 : 1$ (3) $157 : 1$ (4) $191 : 1$ 143. $Uncertainity in position of a particle of 25 g in space is 1 0^{-15} m. Hence, Uncertainity in velocity (in m. se c^{-1}) is: (plank’s constant, h = 6.6 ´ 1 0^{-34} Js)$ (1) $2.1 ´ 1 0^{-18}$ (2) $2.1 ´ 1 0^{-34}$ (3) $0.5 ´ 1 0^{-34}$ (4) $5.0 ´ 1 0^{-24}$ 144. $The electron in the hydrogen atom undergoes transition from higher orbitals to orbitals of radius 211.6 pm. This transition is associated with$ (1) $Paschen series$ (2) $Brackett series$ (3) $Lyman series$ (4) $Balmer series$ 145. $The numbers of d-electrons retained in F e^{2 +} (atomic number Fe = 26) ion is$ (1) $3$ (2) $4$ (3) $5$ (4) $6$ 146. $With what velocity must an electron travel, so that its momentum is equal to that of a photon of wavelength 663 nm ?$ (1) $1098 m / s$ (2) $109.8 m / s$ (3) $10.98 m / s$ (4) $1.098 m / s$ 147. $If the de Broglie wavelength of the electron in n^{t h} Bohr orbit in a hydrogenic atom is equal to 1.5 π a_{0} (a_{0} is Bohr radius), then the value of n/z is:$ (1) $0.75$ (2) $0.40$ (3) $1.0$ (4) $1. 50$ 148. $If wavelength of the first line of the Paschen series of hydrogen atom is 720 nm, then the wavelength of the second line of this scries is _______nm. (Nearest integer)$ 149. $A proton and a L i^{3 +} nucleus are accelerated by the same potential. If ⋋_{Li} and ⋋_{p} denote the de Brogliewavelengths of L i^{3 +} and proton respectively, then the value of \frac{⋋ _{Li}}{⋋ _{p}} is x \times 10^{- 1} . The value of x is ____. [Rounded off to the nearest integer] [Mass of L i^{3 +} = 8.3 mass of proton]$ 150. $Frequency of the de-Broglie wave of electron in Bohr's first orbit of hydrogen atom is ______\times 10^{13} Hz (nearest integer). [Given : R_{H} (Rydberg constant) = 2.18 \times 10^{- 18} J, h (Plank's constant) = 6.6 \times 10^{- 34} J . s .]$