Atomic Structure PYQs Set 9 (PDF)

Set 9 of 14 · Questions 241-270 of 415

In the print window choose “Save as PDF”. The file prints without a web address or date line.

Mere Teacher · Previous Year Questions JEE Main Chemistry · Atomic Structure · Set 9 (Q241-270)
Scan or visit mereteacher.com for free PYQ practice, timed CBT tests, step-by-step solutions and BroBot AI. Answers and solutions are free with a sign-up.
241. $The set of quantum numbers for the outermost electron for copper in its ground state is$ (1) $4, 1, 1, + 1/2$ (2) $3, 2, 2, + 1/2$ (3) $4, 0, 0, + 1/2$ (4) $4, 2, 2, + 1/2$ 242. $Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers, λ = 1 and 2 are, respectively$ (1) $12 and 4$ (2) $12 and 5$ (3) $16 and 4$ (4) $16 and 5$ 243. $A body of mass x kg is moving with a velocity of 100 m s^{- 1} . Its de Broglie wavelength is 6.62 \times 10^{- 35} m . Hence x is (h = 6.62 \times 10^{- 34} Js)$ (1) $0.25 kg$ (2) $0.15 kg$ (3) $0.2 kg$ (4) $0.1 kg$ 244. $Given below are two statements: Statement I : Bohr's theory accounts for thestability and line spectrum of Li^{+} ion. Statement II : Buhr's theory was unable toexplain the splitting of spectral lines in the presence of amagnetic field. In the light of the above statements, choose the most appropriate answer from the options given below:$ (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) $Statement I is true but statement II is false.$ 245. $The energy and radius of electron present in second orbit of He^{+} respectively are$ (1) $- 1.09 \times 10^{- 18} J, 105.8 pm$ (2) $- 8.72 \times 10^{- 18} J, 211.6 pm$ (3) $- 4.36 \times 10^{- 18} J, 52.9 pm$ (4) $- 2.18 \times 10^{- 18} J, 105.8 pm$ 246. $A particular station of All India Radio, New Delhi, broadcasts on a frequency of 1, 368 k Hz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is: [speed of light, c = 3.0 \times 10^{8} ms^{- 1}]$ (1) $219.2 m$ (2) $2192 m$ (3) $21.92 cm$ (4) $219.3 m$ 247. $Identify the region of spectral lines of electromagnetic spectrum, when electron transition takes place from higher energy levels to n = 3, 4, 5 in atomic spectrum of hydrogen is$ (1) $Ultraviolet$ (2) $Visible$ (3) $Infrared$ (4) $Microwave$ 248. $Given below are two statements : Statement-I: Two photons having equal linear momenta have equal wavelengths. Statement-II: If the wavelength of photon is decreased, then the momentum and energy of a photon will alsodecrease. In the light of the above statements, choose the correct answer from the options given below.$ (1) $Statement-I is false but Statement-II is true$ (2) $Both Statement-I and Statement-II are true$ (3) $Both Statement-I and Statement-II are false$ (4) $Statement-I is true but Statement-II is false$ 249. $The correct set of quantum numbers for the unpaired electron of chlorine atom is$ (1) $2, 0, 0, + \frac{1}{2}$ (2) $3, 0, 0, \pm \frac{1}{2}$ (3) $2, 1, - 1, + \frac{1}{2}$ (4) $3, 1, 1, \pm \frac{1}{2}$ 250. $The uncertainty in the position of an electron moving with velocity of 3 \times 10^{4} cm / s is (given mass of electron = 9.1 \times 10^{- 28} g, uncertainty in velocity = 0.02 %)$ (1) $1.8 \times 10^{- 3} cm$ (2) $9 \times 10^{- 3} cm$ (3) $3.8 \times 10^{- 2} cm$ (4) $1.8 \times 10^{- 4} cm$ 251. $In the two elements, Z_{1} A^{M_{1}} and Z_{2} B^{M_{2}}, the following relations are true. M_{1} \neq = M_{2} and Z_{1} \neq = Z_{2} but M_{1} - Z_{1} = M_{2} - Z_{2} . These elements are (M is atomic weight, Z is aomic number)$ (1) $isotonic$ (2) $isobaric$ (3) $isotopic$ (4) $isoelectronic$ 252. $Calculate the energy in joule corresponding to light of wavelength 45 nm. (Planck’s constant, h = 6.63 \times 1 0^{- 34} J s, speed of light, c = 3 \times 1 0^{8} m s^{- 1})$ (1) $6.67 \times 1 0^{15}$ (2) $6.67 \times 1 0^{11}$ (3) $4.42 \times 1 0^{- 15}$ (4) $4.42 \times 1 0^{- 18}$ 253. $The number of radial nodes in 3 s and 2 p -orbitals, respectively are$ (1) $2 : 2$ (2) $2 : 0$ (3) $0 : 0$ (4) $3 : 2$ 254. $Given below are two statements: Statement (I): The radii of isoelectronic species increases in the order. Mg^{2 +} < Na^{+} < F^{-} < O^{2 -} Statement (II): The magnitude of electron gain enthalpy of halogen decreases in the order. Cl > F > Br > I choose the most appropriate answer from the options given below:$ (1) $Statement I is incorrect but Statement II is correct$ (2) $Statement I is correct but Statement II is incorrect$ (3) $Both Statement I and Statement II are incorrect$ (4) $Both Statement I and Statement II are correct$ 255. $Choose the correct statements in reference to the photoelectric effect. (i) There is no time lag between the striking of light and ejection of electrons from the metal surface. (ii) The number of electrons ejected is independent of the intensity of light. (iii) The elements K, Rb and Cs can show photoelectric effect when exposed to the beam of light.$ (1) $(i) and (ii) only$ (2) $(i) and (iii) only$ (3) $(i), (ii), (iii)$ (4) $(ii) and (iii) only$ 256. $The correct statement about probability density (except at infinite distance from nucleus) is$ (1) $It can never be zero for 2 s orbital$ (2) $It can be zero for 3 p orbital$ (3) $It can be zero for 1 s orbital$ (4) $It can be negative for 2 p orbital$ 257. $The masses of an electron, a proton and a neutron respectively will be in the ratio$ (1) $1 : 1836.15 : 1838.68$ (2) $1 : 1856.15 : 1858.68$ (3) $1 : 1834.15 : 1836.68$ (4) $1 : 1846.15 : 1848.68$ 258. $A 100 watt bulb emits light of wavelength ' x' Å . What is the value of x, if the number of photons emitted is 2.0 \times 10^{20} s^{- 1} ? (h = 6.63 \times 10^{- 34} Js, 1) watt (= 1 Js^{- 1})$ (1) $3578$ (2) $4978$ (3) $3978$ (4) $4578$ 259. $The number of protons, neutrons and electrons in_{6}^{13} C respectively are$ (1) $6, 7, 6$ (2) $13, 6, 6$ (3) $6, 7, 13$ (4) $6, 6, 13$ 260. $An element in +2 oxidation state has 24 electrons. The atomic number of the element and the number of unpaired electrons in it respectively are$ (1) $24 and 4$ (2) $26 and 4$ (3) $24 and 2$ (4) $26 and 5$ 261. $According to Bohr's model of hydrogen atom, which of the following statement is incorrect?$ (1) $Radius of 4^{th} orbit is four times larger than that of 2^{nd} orbit$ (2) $Radius of 8^{th} orbit is four times larger than that of 4^{th} orbit$ (3) $Radius of 6^{th} orbit is three times larger than that of 4^{th} orbit$ (4) $Radius of 3^{rd} orbit is nine times larger than that of 1^{st} orbit$ 262. $Maximum number of electrons in a subshell with l = 3 and n = 4 is$ (1) $14$ (2) $16$ (3) $10$ (4) $12$ 263. $The de Broglie wavelength (λ) associated with a photoelectron varies with the frequency (v) of the incident radiation as [v_{0} is threshold frequency] :$ (1) $λ \propto \frac{1}{( v - v _{0} )}$ (2) $λ \propto \frac{1}{( v - v _{0} ) ^{\frac{1}{4}}}$ (3) $λ \propto \frac{1}{( v - v _{0} ) ^{\frac{3}{2}}}$ (4) $λ \propto \frac{1}{( v - v _{0} ) ^{\frac{1}{2}}}$ 264. $The orbital angular momentum of an electron in 2s-orbital is:$ (1) $+ \frac{1}{2} \frac{h}{2 π}$ (2) $zero$ (3) $\frac{h}{2 π}$ (4) $2 \frac{h}{2 π}$ 265. $The total number of electrons that can be accommodated in all the orbitals having principal quantum number 2 and azimuthal quantum number 1 are$ (1) $2$ (2) $4$ (3) $6$ (4) $8$ 266. $The work functions of two metals (M_{A} and M_{B}) are in the 1 : 2 ratio. When these metals are exposed to photons of energy 6 eV, the kinetic energy of liberated electrons of M_{A} : M_{B} is in the ratio of 2.642 : 1 . The work functions (in eV) of M_{A} and M_{B} are respectively.$ (1) $1.4, 2.8$ (2) $2.3, 4.6$ (3) $1.5, 3.0$ (4) $3.1, 6.2$ 267. $The electronic configuration of Cu (atomic number 29) is$ (1) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6}, 4 s^{2} 3 H$ (2) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6} 3 d^{10}, 4 s^{1}$ (3) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6}, 4 s^{2} 4 p^{6}, 5 s^{2} 5 p^{1}$ (4) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6}, 4 s^{2} 4 p^{6} 3 d^{3}$ 268. $A ball weighing 10g is moving with a velocity of 90 m s^{- 1} . If the uncertainty in its velocity is 5%, then the uncertainty in its position is _____\times 10^{- 33} m. (Rounded off to the nearest integer) [Given: h = 6.63 \times 10^{- 34} JS]$ 269. $A source of monochromatic radiation of wavelength 400nm provides 1000J of energy in 10 seconds. When this radiation falls on the surface of sodium, x \times 1 0^{20} electrons are ejected per second. Assume that wavelength 400nm is sufficient for ejection of electron from the surface of sodium metal. The value of x is\dots\dots (Nearest integer) (h = 6.626 \times 10^{- 34} Js)$ 270. $For hydrogen atom, energy of an electron in first excited state is - 3.4 eV, K . E. of the same electron of hydrogen atom is x eV . Value of x is______\times 10^{- 1} eV . (Nearest integer)$