JEE Chemistry Structure of Atoms MCQs A

Question. The mass of a photon with a wavelength equal to 1.54 × 10^–8 cm is
(a) 1.4285 × 10^–32 kg
(b) 0.8268 × 10^–34 kg
(c) None of these
(d) 1.2876 × 10^–33 kg

Answer: A

Question. If the Planck’s constant h = 6.6×10^–34 Js, the de Broglie wavelength of a particle having momentum of 3.3 × 10^–24 kg ms –1 will be
(a) 2Å
(b) 0.002 Å
(c) 0.5Å
(d) 500Å

Answer: A

Question. The values of Planck's constant is 6.63 × 10^–34 Js. The velocity of light is 3.0 × 10⁸ m s^–1. Which value is closest to the wavelength in nanometres of a quantum of light with frequency of 8 × 10¹⁵ s^–1?
(a) 4 × 10¹
(b) 2 × 10^–25
(c) 5 × 10^–18
(d) 3 × 10⁷

Answer: A

Question. The de Broglie wavelength of a car of mass 1000 kg and velocity 36 km/hr is
(a) 6.626 × 10^–38 m
(b) 6.626 × 10^{– 30} m
(c) 6.626 × l0^–34 m
(d) 6.626 × 10^–31 m

Answer: A

Question. Heisenberg's uncertainity principle is applicable to
(a) any moving object
(b) electron only
(c) atoms only
(d) nucleus only

Answer: A

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

Answer: A

Question. Uncertainty in the position of an electron (mass = 9.1 × 10^–31 kg) moving with a velocity 300 ms^–1, accurate upto 0.001% will be (h = 6.63 × 10^–34 Js)
(a) 1.92 × 10^–2 m
(b) 3.84 × 10^–2 m
(c) 5.76 × 10^–2 m
(d) 19.2 × 10^–2 m

Answer: A

Question. The uncertainty in the position of an electron (mass = 9.1 × 10^–28 g) moving with a velocity of 3.0 × 10⁴ cm s^–1 accurate upto 0.011% will be
(a) 0.175 cm
(b) 1.92 cm
(c) 7.68 cm
(d) 3.84 cm

Answer: A

Question. The Heisenberg uncertainity principle will be most significant for which of the following object ?
(a) Object B of mass 9.11 × 10^–28 g
(b) Object A of mass 9.11 × 10^–30 kg
(c) Object C of mass 9.11 × 10^–24 mg
(d) Object D of mass 9.11 × 10^–28 kg

Answer: A

Question. The orientation of an atomic orbital is governed by
(a) Magnetic quantum number
(b) Principal quantum number
(c) Azimuthal quantum number
(d) Spin quantum number

Answer: A

Question. Which of the following represents correct set of the four quantum numbers for an electron in a 4d subshell ?
(a) 4, 2, 1, – 1/2
(b) 4, 3, – 2, – 1/2
(c) 4, 2, 1, 0
(d) 4, 3, 2, + 1/2

Answer: A

Question. The total number of electrons that can be accommodated in all orbitals having principal quantum number 2 and azimuthal quantum number 1 is
(a) 6
(b) 2
(c) 4
(d) 8

Answer: A

Question. What will be the sum of all possible values of l and m for n = 5 ?
(a) 13
(b) 9
(c) 12
(d) 4

Answer: A

Question. The following quantum numbers are possible for how many orbital(s) n = 3, l = 2, m = +2 ?
(a) 1
(b) 3
(c) 4
(d) 2

Answer: A

Question. The orbitals are called degenerate when
(a) they have the same energy
(b) they have different wave functions but same energy
(c) they have the same wave functions but different energies
(d) they have the same wave functions

Answer: A

Question.  The number of spherical nodes in 3p orbitals are
(a) one
(b) three
(c) None of these
(d) two

Answer: A

Question. If there are five radial nodes, then what can be the correct representation of the orbital for n = 8.
(a) 8d
(b) 8p
(c) 8s
(d) 8f

Answer: A

Question. What can be the representation of the orbital having 3 angular nodes and n = 5.
(a) 5f
(b) 5s
(c) 5d
(d) 5p

Answer: A

Question. The number of orbitals present in the fifth shell will be
(a) 25
(b) 50
(c) 10
(d) 20

Answer: A

Question.  Arrange the orbital of same shell in the increasing order of shielding strength of the outer shell of electrons. s, f, d, p
(a) s > p > d > f
(b) s > p < d < f
(c) s < p < d < f
(d) s > p > d < f

Answer: A

Question. The order of filling of electrons in the orbitals of an atom will be
(a) 4s, 3d, 4p, 5s, 4d
(b) 3d, 4p, 4s, 4d, 5s
(c) 3d, 4s, 4p, 4d, 5s
(d) 5s, 4p, 3d, 4d, 5s

Answer: A

Question. Number of unpaired electrons in N²⁺ is
(a) 1
(b) 2
(c) 0
(d) 3

Answer: A

Question. In a given atom no two electrons can have the same values for all the four quantum numbers. This is called
(a) Pauli’s exclusion principle
(b) Aufbau principle
(c) Hund’s Rule
(d) Uncertainty principle

Answer: A