KEAM SERIES Chemistry
Quantum Mechanical Model Of Atom
8 previous year questions.
Volume: 8 Ques
Yield: Medium
High-Yield Trend
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2026 2
2025 1
2022 Chapter Questions 8 MCQs
01
PYQ 2022
medium
chemistry ID: keam-202
A fast moving particle of mass 6.63\times 10-28g can be located with an accuracy of 1A. The uncertainty in its velocity (in ms-1) is about (h=6.63\times 10-34 Js)
1
8\times 103
2
8\times 104
3
8\times 105
4
8\times 106
5
8\times 107
02
PYQ 2025
medium
chemistry ID: keam-202
The orbital described by the quantum numbers and is
1
4s
2
3d
3
2d
4
4f
5
4d
03
PYQ 2025
medium
chemistry ID: keam-202
Total number of orbitals when ?
04
PYQ 2026
medium
chemistry ID: keam-202
Which of the following d-orbital does not have four lobes?}
1
2
3
4
5
05
PYQ 2026
medium
chemistry ID: keam-202
Which of the following statement is incorrect?}
1
The square of the wave function at a point gives the probability density of the electron at that point.
2
For 1s orbital the probability density is maximum at the nucleus and it increases sharply as we move away from it.
3
For 2s orbital the probability density first decreases sharply to zero and again starts increasing.
4
Node is the region where the probability density function of electron reduces to zero.
5
The number of nodes for 3s orbital is 2.
06
PYQ 2026
medium
chemistry ID: keam-202
Which of the following statements are incorrect about boundary surface diagram of orbital?} (i) A boundary surface is drawn in space for an orbital on which the value of probability density is constant.} (ii) The boundary surface for and are not identical.} (iii) The density of the dots represents the probability density of finding the electron in the region.} (iv) In and orbitals, the probability of finding electron at a given distance is not equal in all the directions.} (v) The orbitals in the boundary surface diagram are not spherical.
1
(i), (iv)
2
(iii), (iv)
3
(ii), (iv)
4
(ii), (iii)
5
(i), (ii)
07
PYQ 2026
medium
chemistry ID: keam-202
Which of the following statements are incorrect about boundary surface diagram of orbital?} (i) A boundary surface is drawn in space for an orbital on which the value of probability density is constant.} (ii) The boundary surface for and are not identical.} (iii) The density of the dots represents the probability density of finding the electron in the region.} (iv) In and orbitals, the probability of finding electron at a given distance is not equal in all the directions.} (v) The orbitals in the boundary surface diagram are not spherical.
1
(i), (iv)
2
(iii), (iv)
3
(ii), (iv)
4
(ii), (iii)
5
(i), (ii)
08
PYQ 2026
medium
chemistry ID: keam-202
Which of the following statements are correct about the postulates of quantum mechanical model of an atom? (i) The energy of electron in atom is quantized.
(ii) The existence of quantized electronic energy level is a result of the particle property of electrons.
(iii) The path of the electron can be determined accurately.
(iv) In a multi electron atom, the electrons are filled in various orbitals in the order of increasing energy.
(v) The probability of finding an electron at a point within an atom is proportional to the square of the orbital wave function.
(ii) The existence of quantized electronic energy level is a result of the particle property of electrons.
(iii) The path of the electron can be determined accurately.
(iv) In a multi electron atom, the electrons are filled in various orbitals in the order of increasing energy.
(v) The probability of finding an electron at a point within an atom is proportional to the square of the orbital wave function.
1
(i), (iv), (v)
2
(i), (ii), (iv)
3
(i), (iii), (v)
4
(ii), (iii), (v)
5
(i), (ii), (v)