Atomic Structure PYQs Set 12 (PDF)

Set 12 of 12 · Questions 331-359 of 359

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Mere Teacher · Previous Year Questions NEET Chemistry · Atomic Structure · Set 12 (Q331-359)
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331. $Maximum number of electrons theoretically possible for an orbit with principal quantum number n = 6 in an atom is$ (1) $27$ (2) $98$ (3) $72$ (4) $50$ 332. $How many emission spectral lines are possible when hydrogen atom is excited to n^{th} energy level?$ (1) $\frac{n ( n + 1 )}{2}$ (2) $\frac{( n + 1 )}{2}$ (3) $\frac{( n - 1 ) n}{2}$ (4) $\frac{n ^{2}}{2}$ 333. $The following quantum numbers are possible for how many orbitals: n = 3, l = 2, m = + 2 ?$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 334. $Number of unpaired electrons in N^{2 +} i s / a r e$ (1) $2$ (2) $0$ (3) $1$ (4) $3$ 335. $Which of the following statements do not form a part of Bohr’s model of hydrogen atom?$ (1) $Energy of the electrons in the orbits are quantized.$ (2) $The electron in the orbit nearest the nucleus has the lowest energy.$ (3) $Electrons revolve in different orbits around the nucleus.$ (4) $The position and velocity of the electrons in the orbit cannot be determined simultaneously.$ 336. $Amongst the following statements, that which was not proposed by Dalton was :$ (1) $all the atoms of a given element have identical properties including identical mass. Atoms of different elements differ in mass.$ (2) $chemical reactions involve reorganisation of atoms. These are neither created nor destroyed in a chemical reaction.$ (3) $when gases combine or reproduced in a chemical reaction they do so in a simple ratio by volume provided all gases are at the same T & P .$ (4) $matter consists of indivisible atoms.$ 337. $Which of the following statements are correct, if the threshold frequency of caesium is 5.16 \times 10^{14} Hz ?(A) When Cs is placed inside a vacuum chamber with an ammeter connected to it and yellow light is focused on Cs, the ammeter shows the presence of current.(B) When the brightness of the yellow light is dimmed, the value of the current in the ammeter is reduced.(C) When a red light is used instead of the yellow light, the current produced is higher with respect to the yellow light.(D) When a blue light is used, the ammeter shows the formation of current.(E) When a white light is used. the ammeter shows formation of current. Choose the correct answer from the options given below:$ (1) $B, C and D Only$ (2) $A, C, D and E Only$ (3) $A, B, D and E Only$ (4) $A, D and E Only$ 338. $Which of the following is the energy of a possible excited state of hydrogen ?$ (1) $+13.6 eV$ (2) $-6.8 eV$ (3) $-3.4 eV$ (4) $+6.8 eV$ 339. $Which of the following combination of statements is true regarding the interpretation of the atomic orbitals ? (1) An electron in an orbital of high angular momentum stays away from the nucleus than an electron in the orbital of lower angular momentum. (2) For a given value of the principal quantum number, the size of the orbit is inversely proportional to the azimuthal quantum number. (3) According to wave mechanics, the ground state angular momentum is h equal to \frac{h}{2 π} . (4) The plot of ψ vs for various azimuthal quantum numbers, show peak shifting towards a higher value.$ (1) $(1), (4)$ (2) $(1), (2)$ (3) $(1), (3)$ (4) $(2), (3)$ 340. $The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is: [Given: The threshold frequency of platinum is 1.3 x 1 0^{15} s^{- 1} and h = 6. 6 x 1 0^{- 34} Js.]$ (1) $3.21 x 1 0^{44} J$ (2) $6.24 x 1 0^{- 16} J$ (3) $8.58 x 1 0^{- 19} J$ (4) $9.76 x 1 0^{- 20} J$ 341. $Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Energy of 2s orbital of hydrogen atom is greater than that of 2s orbital of lithium. Reason R : Energies of the orbitals in the same subshell decrease with increase in the atomic number. In the light of the above statements, choose the correct answer from the options given below.$ (1) $Both A and R are true and R is the correct explanation of A.$ (2) $Both A and R are true but R is NOT the correct explanation of A.$ (3) $A is true but R is false.$ (4) $A is false but R is true.$ 342. $The orbital angular momentum of a p ‐electron is given as$ (1) $\frac{h}{2 π}$ (2) $3 \frac{h}{2 π}$ (3) $\frac{3}{2} \frac{h}{π}$ (4) $6 \frac{h}{2 π}$ 343. $The outer electronic configuration of Gd (At. No. 64) is$ (1) $4 f^{5} 5 d^{4} 6 s^{1}$ (2) $4 f^{7} 5 d^{1} 6 s^{2}$ (3) $4 f^{3} 5 d^{5} 6 s^{2}$ (4) $4 f^{4} 5 d^{5} 6 s^{1}$ 344. $Based on equation E = - 2.178 \times 1 0^{- 18} J (\frac{Z ^{2}}{n ^{2}}), certain conclusions are written. Which ofthem is not correct?$ (1) $Equation can be used to calculate the change in energy when the electron changes orbit.$ (2) $For n = 1, the electron has a more negative energy than it does for n = 6 which means that the electron is more loosely bound in the smallest allowed orbit.$ (3) $The negative sign in equation simply means that the energy of electron bound to the nucleus is lower than it would be if the electrons were at the infinite distance from the nucleus.$ (4) $Larger the value of n, the larger is the orbit radius.$ 345. $Which one of the following sets of ions represents a collection of isoelectronic species?(Given : Atomic Number : F :9 , Cl : 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21)$ (1) $L i^{+}, N a^{+}, M g^{2 +}, C a^{2 +}$ (2) $B a^{2 +}, S r^{2 +}, K+ , C a^{2 +}$ (3) $N^{3 -}, O^{2 -}, F^{-}, S^{2 -}$ (4) $K^{+}, C l^{-}, C a^{2 +}, S c^{3 +}$ 346. $Consider the following pairs of electrons (A) (a) n = 3, l = 1, m_{l} = 1, m_{s} = + \frac{1}{2} (b) n = 3, l = 2, m_{l} = 1, m_{s} = + \frac{1}{2} (B) (a) n = 3, l = 2, m_{l} = - 2, m_{s} = - \frac{1}{2} (b) n = 3, l = 2, m_{l} = -1, m_{s} = - \frac{1}{2} (C) (a) n = 4, l = 2, m_{l} = 2, m_{s} = + - \frac{1}{2} (b) n = 3, l = 2, m_{l} = 2, m_{s} = + \frac{1}{2} The pairs of electron present in degenerate orbitals is/are:$ (1) $Only A$ (2) $Only B$ (3) $Only C$ (4) $(b) and (c)$ 347. $Choose the Incorrect Statement about Dalton's Atomic Theory$ (1) $chemical reactions involve reorganization of atoms$ (2) $Matter consists of indivisible atoms.$ (3) $Compounds are formed when atoms of different elements combine in any ratio.$ (4) $All the atoms of a given element have identical properties including identical mass.$ 348. $The order of filling of electrons in orbitals in Ti is$ (1) $1 s, 2 s, 2 p, 3 s, 3 p, 3 d and 4 s$ (2) $1 s, 2 s, 2 p, 3 s, 3 p, 4 s and 3 d$ (3) $1 s, 2 s, 2 p, 3 s, 4 s, 3 p and 3 d$ (4) $1 s, 2 s, 2 p, 3 s, 3 d, 3 p and 4 s$ 349. $The work functions of Ag, Mg, K and Na respectively in eV are 4.3, 3.7, 2.25, 2.30. When an electromagnetic radiation of wavelength of 300 nm is allowed to fall on these metal surface, the number of metals from which the electrons are ejected is (1 eV = 1.6022 \times 10^{- 19} J)$ (1) $4$ (2) $3$ (3) $2$ (4) $5$ 350. $Which of the following statements is correct about the cathode rays? 1.These rays start from anode and move towards cathode. 2.They are visible with human eye. 3.In presence of electric and magnetic fields, they behave like positively charged particles. 4.Their characteristic does not depend on the nature of material at electrode.$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 351. $Which quantum number provides information about the shape of an orbital?$ (1) $Spin quantum number$ (2) $Azimuthal quantum number$ (3) $Magnetic quantum number$ (4) $Principal quantum number$ 352. $Heisenberg's uncertainty principle is in general significant to$ (1) $planets$ (2) $cricket ball of 500 g$ (3) $cars$ (4) $micro particles having a very high speed$ 353. $The energy of electron in the n^{th} Bohr orbit of H -atom is$ (1) $\frac{- 13.6}{n ^{2}} eV$ (2) $\frac{- 13.6}{n} eV$ (3) $\frac{- 13.6}{n ^{4}} eV$ (4) $\frac{- 13.6}{n ^{3}} eV$ 354. $If n = 6, the correct sequence for filling of electrons will be$ (1) $n s \to_{(} n - 2_{)} f \to_{(} n - 1_{)} d \to n p$ (2) $n s \to_{(} n - 1_{)} d \to_{(} n - 2_{)} f \to n p$ (3) $n s \to_{(} n - 2_{)} f \to n p \to_{(} n - 1_{)} d$ (4) $n s \to n p \to_{(} n - 1_{)} d \to_{(} n - 2_{)} f$ 355. $The incorrect postulates of the Dalton's atomic theory are : (A) Atoms of different elements differ in mass.(B) Matter consists of divisible atoms.(C) Compounds are formed when atoms of different element combine in a fixed ratio.(D) All the atoms of given element have different properties including mass.(E) Chemical reactions involve reorganisation of atoms. Choose the correct answer from the options given below :$ (1) $(C), (D), (E) only$ (2) $(B), (D) only$ (3) $(A), (B), (D) only$ (4) $(B), (D), (E) only$ 356. $"No two electrons in an atum can have the same set of all four quantum numbers". This principle of called$ (1) $Zeeman effect$ (2) $Pauli's exclusion principle$ (3) $Stark effect$ (4) $Heisenberg principle$ 357. $Match List I with List II List I (Spectral Series for Hydrogen) A. Lyman B. Balmer C. Paschen D. Pfund List II (Spectral Region/Higher Energy State) I. Infrared region II. UV region III. Infrared region IV. Visible region Choose the correct answer from the options given below :-$ (1) $A-II, B-III, C-I, D-IV$ (2) $A-I, B-III, C-II, D-IV$ (3) $A-II, B-IV, C-III, D-I$ (4) $A-I, B-II, C-III, D-IV$ 358. $The shortest wavelength of hydrogen atom in Lyman scries is λ . The longest wavelength in Balmer series of H e^{+} is$ (1) $\frac{5}{9 λ}$ (2) $\frac{9 λ}{5}$ (3) $\frac{36 λ}{5}$ (4) $\frac{5 λ}{9}$ 359. $Given below are two statements about X-ray spectra of elements: Statement (I): A plot of v (v = frequency of X -rays emitted) vs atomic mass is a straight line. Statement (II): A plot of v (v = frequency of X -rays emitted) vs atomic number is a straight line. choose the correct answer from the options given below:$ (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) $Statement I is true but Statement II is false$