NEET Chemistry Structure Of Atom MCQs Set B

Question:  Two particles A and B are in motion. If the wavelength associated with particle A is 5 × 10^–8 m; calculate the wavelength associated with particle B if its momentum is half of A.

• a) 5 × 10^–8 m 
• b) 10^–5 cm
• c) 10^–7 cm
• d) 5 × 10^–8 cm

Answer:  10^–5 cm

Question: Any f-orbital can accommodate upto

• a) 2 electrons with parallel spin
• b) 6 electrons
• c) 2 electrons with opposite spin
• d) 14 electrons

Answer: 2 electrons with opposite spin

Question: Total number of spectral lines in UV region, during transition from 5th excited state to 1st excited state

• a) 10
• b) 3
• c) 4
• d) Zero

Answer: Zero

Question: For principal quantum number n = 5, the total number of orbitals having l = 3 is

• a) 7
• b) 14
• c) 9
• d) 18

Answer: 7

Question: The first emission line in the atomic spectrum of hydrogen in the Balmer series appears at

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The four quantum numbers of valence electron of potassium are

• a) 4, 0, 1,1/2
• b) 4, 1, 0,1/2
• c) 4, 0, 0,1/2
• d) 4, 1, 1,1/2

Answer: 4, 0, 0,1/2

Question:  In a hydrogen atom, if the energy of electron in the ground state is –x eV., then that in the 2nd excited state of He⁺ is

• a) –x eV
• b)

  

• c) +2x eV
• d)

  

Answer:

Question: In the ground state, an element has 13 electrons in its M-shell. The element is

• a) Manganese
• b) Cobalt
• c) Nickel
• d) Iron

Answer: Manganese

Question:  The wavelength of radiation emitted, when in He⁺ electron falls from infinity to stationary state would be (R = 1.097 × 10⁷ m^–1)

• a) 2.2 × 10^–8 m
• b) 22 × 10^–9 m
• c) 120 m
• d) 22 × 10⁷ m

Answer:  2.2 × 10^–8 m

Question: In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen?

• a) 3→ 1
• b) 5 → 2
• c) 2→ 5
• d) 3→ 2

Answer:  5 → 2

Question: The correct order of energy difference between adjacent energy levels in H atom

• a) E₂– E₁> E₃– E₂> E₄– E₃    
• b) E₂– E₁> E₄– E₃> E₃– E₂ 
• c) E₄– E₃> E₃– E₂> E₂– E₁  
• d) E₃– E₂> E₄– E₃> E₂– E₁

Answer:   E₂– E₁> E₃– E₂> E₄– E₃    

Question: Which of the following electronic in a transition hydrogen atom will require the largest amount of energy?

• a) n = 1 to n = 2
• b) n = 2 to n = 3
• c) n = 1 to n = ∞ 
• d) n = 3 to n = 5

Answer:  n = 1 to n = ∞ 

Question: Which combinations of quantum numbers n, l, m and s for the electron in an atom does not provide a permissible solutions of the wave equation?

• a) 3, 2, -2,1/2
• b) 3, 3, 1,-1/2
• c) 3, 2, 1,1/2
• d) 3, 1, 1,-1/2

Answer: 3, 3, 1,-1/2

Question: The orbital angular momentum of electron in 4s orbital is

• a)

  

• b) Zero
• c)

  

• d)

  

Answer: Zero

Question: Radial nodes present in 3s and 3p-orbitals are respectively

• a) 0, 2
• b) 2, 1
• c) 1, 1
• d) 2, 2

Answer: 2, 1

Question: The number of lobes in most of the d-orbitals are

• a) 6
• b) 8
• c) 10
• d) 4

Answer: 4

Question:    Quantum numbers for some electrons are given below

A : n = 4, l = 1

B : n = 4, l = 0

C : n = 3, l = 2

D : n = 3, l = 1

The correct increasing order of energy of electrons

• a) A < B < C < D
• b) D < C < B < A
• c) D < B < C < A
• d) C < B < A < D

Answer: D < B < C < A

Question: For which of the following options m = 0 for all orbitals?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:   Which is the correct graphical representation based on photoelectric effect?

• a) I & II
• b) II & III
• c) III & IV
• d) II & IV

Answer: II & IV

Question: The time taken by the electron in one complete revolution in the nth Bohr’s orbit of the hydrogen atom is

• a)  Inversely proportional to n²
• b) Directly proportional to n³
• c)

  

• d)

  

Answer:  Directly proportional to n³

Question: What will be the ratio of the wavelength of the first line to that of the second line of Paschen series of H atom?

• a) 256 : 175
• b) 175 : 256
• c) 15 : 16
• d) 24 : 27

Answer: 256 : 175

Question: In any sub-shell, the maximum number of electrons having same value of spin quantum number is

• a)

  

• b) l + 2
• c) 2l + 1
• d) 4l + 2

Answer: 2l + 1

Question:   For the transition from n = 2 → n = 1, which of the following will produce shortest wavelength?

• a) H atom
• b) D atom
• c) He⁺ ion
• d) Li²⁺ ion

Answer:  Li²⁺ ion

Question: If each orbital can hold a maximum of 3 electrons. The number of elements in 2nd period of periodic table (long form) is

• a) 27
• b) 9
• c) 18
• d) 12

Answer: 12

Question: The angular momentum of electron in 'd' orbital is equal t

• a) 0 h
• b) √6 h 
• c) √2 h 
• d) 2 √3 h

Answer:  √6 h 

Question:   What is the maximum number of orbitals that can be identified with the following quantum numbers?

n = 3, l = l, m_l = 0 

• a) 1
• b) 2
• c) 3
• d) 4

Answer: 1

Question:  Calculate the energy in joule corresponding to light of wavelength 45 nm: (Planck's constant h = 6.63 × 10^–34 Js; speed of light c = 3 × 10⁸ ms^–1)

• a) 6.67 × 10¹⁵ 
• b) 6.67 × 10¹¹
• c) 4.42 × 10^–15
• d) 4.42 × 10^–18

Answer:  4.42 × 10^–18

Question:  Be²⁺ is isoelectronic with which of the following ions ? 

• a) H⁺ 
• b) Li⁺ 
• c) Na⁺
• d) Mg²

Answer:   Li⁺ 

Question: What is the maximum numbers of electrons that can be associated with the following set of quantum numbers? n = 3, l = 1 and m = –1

• a) 6
• b) 4
• c) 2
• d) 10

Answer: 2

Question:  The value of Planck's constant is 6.63 × 10^–34 Js. The speed of light is 3 × 10¹⁷ nm s^–1. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of 6 × 10¹⁵ s^–1? 

• a) 25
• b) 50
• c) 75
• d) 10

Answer: 50

Question:  Based on equation 

certain conclusions are written. Which of them is not correct?

• a) Larger the value of n, the larger is the orbit radius
• b) Equation can be used to calculate the change in energy when the electron changes orbit
• c) 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 Sol. Answer (3)
• d) 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

Answer: 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 Sol. Answer (3)

Question: The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Maximum number of electrons in a subshell with l = 3 and n = 4 is

• a) 10
• b) 12
• c) 14
• d) 16

Answer: 14

Question: The orbital angular momentum of a p-electron is given as

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The total number of atomic orbitals in fourth energy level of an atom is

• a) 4
• b) 8
• c) 16
• d) 32

Answer: 16

Question:   The energies E₁ and E₂ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e. λ₁ and λ₂ will be

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: If n = 6, the correct sequence of filling of electrons will be

• a) ns →(n →1)d→(n → 2)f 
• b) ns →(n → 2)f →(n →1)d→np
• c) ns →(n →1)d→(n → 2)f →np 
• d) ns →(n → 2)f →np →(n →1)d

Answer:  ns →(n → 2)f →(n →1)d→np

Question: According to the Bohr Theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon?

• a) n = 6 to n = 5
• b) n = 5 to n = 3
• c) n = 6 to n = 1
• d) n = 5 to n = 4

Answer: n = 6 to n = 5

Question:  A 0.66 kg ball is moving with a speed of 100 m/s. The associated wavelength will be (h = 6.6 × 10^–34 Js)

• a) 6.6 × 10^–32 m 
• b) 6.6 × 10^–34 m 
• c) 1.0 × 10^–35 m 
• d) 1.0 × 10^–32 m

Answer:  1.0 × 10^–35 m 

Question:  The energy absorbed by each molecule (A₂) of a substance is 4.4 × 10^–19J and bond energy per molecule is 4.0 ×10^–19 J. The kinetic energy of the molecule per atom will be 

• a) 2.2 × 10^–19 J
• b) 2.0 × 10^–19 J 
• c) 4.0 × 10^–20J 
• d) 2.0 × 10^–20J

Answer:  2.0 × 10^–20J

Question: Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidation states?

• a) 3d⁵4s¹
• b) 3d⁵4s²
• c) 3d²4s² 
• d) 3d³4s²

Answer: 3d⁵4s²

Question: Maximum number of electrons in a subshell of an atom is determined by the following

• a)

  

• b)

  

• c)

  2n²

• d)

  

Answer:

Question: Which of the following is not permissible arrangement of electrons in an atom?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly

• a) 20 × 10¹⁴ Hz 
• b) 10 × 10¹⁴ Hz
• c) 5 × 10¹⁴ Hz 
• d) 1 × 10¹⁴ Hz

Answer:   5 × 10¹⁴ Hz 

Question: If uncertainty in position and momentum are equal, then uncertainty in velocity is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  The measurement of the electron position is associated with an uncertainty in momentum, which is equal to 1× 10^–18 g cm s^–1. The uncertainty in electron velocity is, (Mass of an electron is 9 × 10^–28g)

• a) 1 × 10¹¹ cm s^–1
• b) 1 × 10⁹ cm s^–1 
• c) 1 × 10⁶ cm s^–1 
• d) 1 × 10⁵ cm s^–1

Answer:  1 × 10⁹ cm s^–1 

Question:  Consider the following sets of quantum numbers 

Which of the following sets of quantum number is not possible? 

• a) a and c
• b) b, c and d
• c) a, b, c and d
• d) b, d and e

Answer: b, d and e

Question: With which of the following configuration an atom has the lowest ionization enthalpy ?

• a) 1s² 2s² 2p⁶
• b) 1s² 2s² 2p⁵
• c) 1s² 2s² 2p³
• d) 1s² 2s² 2p⁵ 3s¹

Answer:  1s² 2s² 2p⁵ 3s¹

Question:  Given : The mass of electron is 9.11×10^–31 kg. Planck’s constant is 6.626×10^–34 Js, the uncertainty involved in the measurement of velocity within a distance of 0.1 Å is 

• a) 5.79 × 10⁶ ms^–1 
• b) 5.79 × 10⁷ ms^–1 
• c) 5.79 × 10⁸ ms^–1
• d) 5.79 × 10⁵ ms^–1

Answer:  5.79 × 10⁶ ms^–1 

Question: The orientation of an atomic orbital is governed by

• a) Azimuthal quantum number
• b) Spin quantum number
• c) Magnetic quantum number
• d) Principal quantum number

Answer: Magnetic quantum number

Question:  The energy of second Bohr orbit of the hydrogen atom is –328 kJ mol^–1; hence the energy of fourth Bohr orbit would be

• a) –41 kJ mol^–1 
• b) –1312 kJ mol^–1
• c) –164 kJ mol^–1
• d) –82 kJ mol^–1

Answer:  –82 kJ mol^–1

Question:  Uncertainty in position of an electron (mass = 9.1 × 10^–28g) moving with a velocity of 3 × 10⁴ cm/s accurate upto 0.001% will be (Use h/(4π) in uncertainty expression where h = 6.626 × 10^–27 erg-s)

• a) 5.76 cm
• b) 7.68 cm
• c) 1.93 cm
• d) 3.84 cm

Answer: 1.93 cm

Question:  The radius of hydrogen atom in the ground state is 0.53 Å. The radius of Li²⁺ ion (atomic number = 3) in a similar state is

• a) 0.53 Å 
• b) 1.06 Å 
• c) 0.17 Å
• d) 0.265 Å

Answer: 0.17 Å

Question: In a Bohr’s model of an atom, when an electron jumps from n = 1 to n = 3, how much energy will be emitted or absorbed?

• a) 2.389 × 10^–12 ergs
• b) 0.239 × 10^–10 ergs
• c) 2.15 × 10^–11 ergs
• d) 0.1936 × 10^–10 ergs

Answer: 0.1936 × 10^–10 ergs

Question: The electronic configuration of gadolinium (Atomic No. 64) is

• a) [Xe]4f ³ 5d⁵ 6s²
• b) [Xe]4f ⁶ 5d² 6d² 
• c) [Xe]4f⁸ 5d⁹ 6s²
• d) [Xe] 4f ⁷ 5d¹ 6s²

Answer: [Xe] 4f ⁷ 5d¹ 6s²

Question: The ion that is isoelectronic with CO is

• a) CN^– 
• b) N₂⁺ 
• c) O₂^– 
• d) N₂^–

Answer:  CN^– 

Question: The Bohr orbit radius for the hydrogen atom (n = 1) is approximately 0.530 Å. The radius for the first excited state (n = 2) orbit is (in Å)

• a) 4.77
• b) 1.06
• c) 0.13
• d) 2.12

Answer: 2.12

Question:  The position of both, an electron and a helium atom is known within 1.0 nm. Further the momentum of the electron is known within 5.0 × 10^–26 kg ms^–1. The minimum uncertainty in the measurement of the momentum of the helium atom is

• a) 8.0 × 10^–26 kg ms^–1
• b) 80 kg ms^–1 
• c) 50 kg ms^–1 
• d) 5.0 × 10^–26 kg ms^–1

Answer:  5.0 × 10^–26 kg ms^–1

Question: Who modified Bohr’s theory by introducing elliptical orbits for electron path?

• a) Rutherford
• b) Thomson
• c) Hund
• d) Sommerfield

Answer: Sommerfield

Question: The following quantum numbers are possible for how many orbitals : n = 3, l = 2, m = +2?

• a) 1
• b) 2
• c) 3
• d) 4

Answer: 1