NEET Chemistry Structure Of Atom MCQs Set A

Question:  An isotone of 

Ge is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The ratio of specific charge of an electron to that of a proton is

• a) 1 : 1
• b) 1837 : 1
• c) 1 : 1837
• d) 2 : 1

Answer: 1837 : 1

Question:  Atomic number and mass number of an element M are 25 and 52 respectively. The number of electrons, protons and neutrons in M²⁺ ion are respectively

• a) 25, 25 and 27
• b) 25, 27 and 25
• c) 27, 25 and 27
• d) 23, 25 and 27

Answer: 23, 25 and 27

Question: According to Bohr’s theory angular momentum of an electron in 6th orbit is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  If r₁ is the radius of the first orbit of hydrogen atom, then the radii of second, third and fourth orbits in term of r₁ are

• a) r₁², r₁³, r₁⁴
• b) 4r₁ , 9r₁ , 16r₁
• c) 8r₁, 27r₁, 64r₁
• d) 2r₁, 6r₁, 8r₁

Answer:  4r₁ , 9r₁ , 16r₁

Question: Electronic energy is negative because

• a) Electron has negative charge
• b) Energy is zero near the nucleus and decreases as the distance from nucleus increases
• c) Energy is zero at infinite distance from the nucleus and decreases as the electron comes towards nucleus
• d) These are interelectronic repulsions

Answer: Energy is zero at infinite distance from the nucleus and decreases as the electron comes towards nucleus

Question: An electron jumps from lower orbit to higher orbit, when

• a) Energy is released
• b) Energy is absorbed
• c) No change in energy
• d) It radiates energy

Answer: Energy is absorbed

Question:   If the energy difference between the ground state and excited state of an atom is 4.4 × 10^–19 J. The wavelength of photon required to produce this transition is

• a) 4.5 × 10^–7 m
• b) 4.5 × 10^–7 nm
• c) 4.5 × 10^–7 Å 
• d) 4.5 × 10^–7 cm

Answer:  4.5 × 10^–7 m

Question:  The number of photons of light of wavelength 7000 Å equivalent to 1 J are

• a) 3.52 × 10^–18 
• b) 3.52 × 10¹⁸ 
• c) 50,000
• d) 10,0000

Answer:  3.52 × 10¹⁸ 

Question:   The threshold energy is given as E₀ and radiation of energy E falls on metal, then K.E. is given as

• a)

  

• b) E – E₀
• c) E₀– E
• d)

  

Answer:  E – E₀

Question:  The frequency of a wave is 6 × 10¹⁵ s^–1. Its wave number would be

• a) 10⁵ cm^–1
• b) 2 × 10⁷ m^–1
• c) 2 × 10⁷ cm^–1
• d) 2 × 10⁵ cm^–1

Answer:  2 × 10⁷ m^–1

Question:  If threshold wavelength (λ°) for ejection of electron from metal is 330 nm, then work function for the photoelectric emission is

• a) 6 × 10^–10 J
• b) 1.2 × 10^–18 J 
• c) 3 × 10^–19 J 
• d) 6 × 10^–19 J

Answer:  6 × 10^–19 J

Question: The ionization energy of the electron in the lowest orbit of hydrogen atom is 13.6 eV. The energies required in eV to remove electron from three lowest orbits of hydrogen atom are

• a) 13.6, 6.8, 8.4
• b) 13.6, 10.2, 3.4
• c) 13.6, 27.2, 40.8
• d) 13.6, 3.4, 1.51

Answer: 13.6, 3.4, 1.51

More Questions........................................................

Question:  A certain metal when irradiated with light (v = 3.2 × 10¹⁶ Hz) emits photo electrons with twice kinetic energy as did photo electrons when the same metal is irradiated by light (v = 2.0 × 10¹⁶ Hz). Calculate v₀ of electron?

• a) 1.2 × 10¹⁴ Hz
• b) 8 × 10¹⁵ Hz 
• c) 1.2 × 10¹⁶ Hz
• d) 4 × 10¹² Hz

Answer:  8 × 10¹⁵ Hz 

Question:  E_n = –313.6/n² kcal/mole. If the value of E = –34.84 kcal/mole, to which value does ‘n’ correspond?

• a) 4
• b) 3
• c) 2
• d) 1

Answer: 3

Question:  Which transition of Li²⁺ is associated with same energy change as n = 6 to n = 4 transition in He⁺?

• a) n = 3 to n = 1
• b) n = 8 to n = 6
• c) n = 9 to n = 6
• d) n = 2 to n = 1

Answer: n = 9 to n = 6

Question: Zeeman effect refers to the

• a) Splitting of the spectral lines in a magnetic field
• b) Splitting up of the spectral lines in an electrostatic field
• c) Emission of electrons from metals when light falls on it
• d) Random scattering of α-particles by gold foil

Answer: Splitting of the spectral lines in a magnetic field

Question: Number of spectral lines in Balmer series when an electron return from 7th orbit to 1st orbit of hydrogen atom are

• a) 5
• b) 6
• c) 21
• d) 15

Answer: 5

Question: If kinetic energy of a proton is increased nine times, the wavelength of the de-Broglie wave associated with it would become

• a) 3 times
• b) 9 times
• c) 1/3 times
• d) 1/9 times

Answer: 1/3 times

Question: The number of waves in the third orbit of H atom is

• a) 1
• b) 2
• c) 4
• d) 3

Answer: 3

Question: The de-Broglie wavelength of an electron travelling with 10% of velocity of light is equal to

• a) 242.4 pm
• b) 24.2 pm
• c) 2.42 pm
• d) 2.424 pm

Answer: 24.2 pm

Question: The wavelength associated with a ball of 200 g and moving with a speed of 5 m/hour is of the order of

• a) 10^–10 m
• b) 10^–20 m
• c) 10^–30 m
• d) 10^–40 m

Answer:  10^–30 m

Question: The momentum of a particle which has a de-Broglie wavelength of 0.1 nm is

• a) 3.2 × 10^–24 kg ms^–1 
• b) 4.3 × 10^–22 kg ms^–1
• c) 5.3 × 10^–22 kg ms^–1 
• d) 6.62 × 10^–24 kg ms^–1

Answer: 6.62 × 10^–24 kg ms^–1

Question:  The uncertainty in velocity of an electron present in the nucleus of diameter 10^–15m hypothetically should be approximately

• a) 10^–11 m/s
• b) 10⁸ m/s
• c) 10¹¹ m/s
• d) 10 Å/s

Answer:  10¹¹ m/s

Question:  The set of quantum numbers not applicable to an electron

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The principal and azimuthal quantum number of electrons in 4f orbitals are

• a) 4, 2
• b) 4, 4
• c) 4, 3
• d) 3, 4

Answer: 4, 3

Question:  How many 3d electrons can have spin quantum number  ?

• a) 5
• b) 7
• c) 8
• d) 10

Answer: 5

Question: The correct order of increasing energy of atomic orbital is

• a) 5p < 4f < 6s < 5d
• b) 5p < 6s < 4f < 5d
• c) 4f < 5p < 5d < 6s
• d) 5p < 5d < 4f < 6s

Answer: 5p < 6s < 4f < 5d

Question: Which shell would be the first to have ‘g’ sub-shell?

• a) L
• b) M
• c) N
• d) O

Answer: O

Question: For which one of the following set of quantum numbers an electron will have the highest energy?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The energies of orbitals of H-atom are in the order

• a) 3s < 3p < 4s < 3d < 4p
• b) 3s < 3p < 3d < 4s < 4p
• c) 3s = 3p = 3d < 4s = 4p
• d) 3s = 3p = 3d < 4s < 4p

Answer: 3s = 3p = 3d < 4s = 4p

Question: Which of the following set of quantum number is possible?

• a) n = 4, l = 2, m = –2, s = –2
• b) n = 4, l = 4, m = 0, s =1/2
• c) n = 4, l = 3, m = –3, s =1/2
• d) n = 4, l = 0, m = 0, s = 0

Answer: n = 4, l = 3, m = –3, s =1/2

Question: The maximum number of electrons in an atom which can have n = 4 is

• a) 4
• b) 8
• c) 16
• d) 32

Answer: 32

Question: In the presence of magnetic field, the possible number of orientations for an orbital of azimuthal quantum number 3, is

• a) Three
• b) One
• c) Five
• d) Seven

Answer: Seven

Question: Assuming the velocity to be same, the wavelength of the waves associated with which of the following particles would be maximum?

• a) An electron
• b) A proton
• c) An α-particle
• d) A deutron

Answer: An electron

Question: For a ‘p’ electron, the orbital angular momentum is

• a)

  

• b)

  

• c) h
• d) 2h

Answer:

Question: Which of the following electronic level would allow the hydrogen to absorb a photon but not emit a photon?

• a) 3s
• b) 2p
• c) 2s
• d) 1s

Answer: 1s

Question: Which of the following transition will emit maximum energy in hydrogen atom?

• a) 4f → 2s
• b) 4d → 2p
• c) 4p →2s 
• d) All have same energy

Answer: All have same energy

Question: In an atom, which has 2K, 8L, 18M and 2N electrons in the ground state. The total number of electrons having magnetic quantum number, m = 0 is

• a) 6
• b) 10
• c) 7
• d) 14

Answer: 14

Question: The probability density curve for 2s electron appears like

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A p-orbital can accommodate upto

• a) Four electrons
• b) Six electrons
• c) Two electrons
• d) Eight electrons

Answer: Two electrons

Question: If the uncertainty in the position of electron is zero, the uncertainty in its momentum would be

• a) Zero
• b)

  

• c)

  

• d) Infinite

Answer: Infinite

Question: The number of radial nodes in 4s and 3p orbitals are respectively

• a) 2, 0
• b) 3, 1
• c) 2, 2
• d) 3, 2

Answer: 3, 1

Question: Which of the following orbital is with the four lobes present on the axis?

• a) d_z² 
• b) d_xy 
• c) d_yz   
• d) d_x²-y²

Answer:  d_x²-y²

Question: Which of the following statement concerning the four quantum number is incorrect?

• a) n gives the size of an orbital
• b) l gives the shape of an orbital
• c) m gives the energy of the electron in orbital
• d) s gives the direction of spin of electron in the orbital

Answer: m gives the energy of the electron in orbital

Question: Which of the following has maximum number of unpaired electrons?

• a) Mg²⁺
• b) Ti³⁺
• c) Fe²⁺
• d) Mn²⁺

Answer:  Mn²⁺

Question: Two electrons in K shell will not have

• a) Same principal quantum number
• b) Same azimuthal quantum number
• c) Same magnetic quantum number
• d) Same spin quantum number

Answer: Same spin quantum number

Question: The orbital diagram in which both Pauli’s exclusion principle and Hund’s rule are violated is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following electronic configuration is not possible?

• a) 2p³ 
• b) 2d⁵
• c) 4s¹ 
• d) 5f⁸

Answer:  2d⁵

Question: Which of the following electronic configuration is incorrect?

• a) 1s², 2s², 2p_x², 2p_y², 2p_z², 3s², 3p_x¹
• b) 1s², 2s¹, 2p_x¹, 2p_y¹, 2p_z¹
• c) 1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁵, 4s²
• d) 1s², 2s², 2p⁶, 3s², 3p_x¹, 3p_y¹, 3p_z¹

Answer:   1s², 2s¹, 2p_x¹, 2p_y¹, 2p_z¹

Question: What will be the longest wavelength line in Balmer series of spectrum of H-atom?

• a) 546 nm
• b) 656 nm
• c) 566 nm
• d) 556 nm

Answer: 656 nm

Question:  The uncertainty in momentum of an electron is 1 × 10^–5 kg-m/s. The uncertainty in its position will be (h = 6.62 × 10^–34 kg-m²/s)

• a) 5.27 × 10^–30 m
• b) 1.05 × 10^–26 m
• c) 1.05 × 10^–28 m
• d) 5.25 × 10^–28 m

Answer:  5.27 × 10^–30 m

Question: In hydrogen atom, energy of first excited state is –3.4 eV. Then find out KE of same orbit of hydrogen atom

• a) +3.4 eV
• b) +6.8 eV
• c) –13.6 eV
• d) +13.6 eV

Answer: +3.4 eV

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 total number of subshells in fourth energy level of an atom is

• a) 4
• b) 8
• c) 16
• d) 32

Answer: 4

Question: For which of the following sets of four quantum numbers, an electron will have the highest energy?

• a)

  n    l      m      s

  3   2      1      +1/ 2

• b)

  n      l     m        s

  4    2      –1    +1/2

   

• c)

  n      l     m       s

  4     1     0     – 1/2

• d)

  n      l       m     s

  5     0       0    –1/2

Answer:

n      l     m        s

4    2      –1    +1/2

Question:  A transition element X has a configuration (Ar)3d ⁴ in its +3 oxidation state. Its atomic number is

• a) 22
• b) 19
• c) 25
• d) 26

Answer: 25

Question: Among the following which one is not paramagnetic? [Atomic numbers; Be = 4, Ne = 10, As = 33, Cl = 17]

• a) Ne²⁺
• b) Be⁺
• c) Cl^– 
• d) As⁺

Answer: Cl^– 

Question: Isoelectronic species are

• a) CO, CN^–, NO⁺, C₂^2–
• b) CO^–, CN, NO, C₂^–
• c) CO⁺, CN⁺, NO^–, C₂
• d) CO, CN, NO, C₂

Answer:  CO, CN^–, NO⁺, C₂^2–

Question:  Consider the following sets of quantum number

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

• a) (i), (ii), (iii) and (iv)
• b) (ii), (iv) and(v) 
• c) (i) and (iii) 
• d) (ii), (iii) and (iv)

Answer:   (ii), (iv) and(v)