CBSE Class 11 Chemistry VBQs Structure Of Atom

Question. Neutrons are present in all atoms except
(A) H.
(B) C.
(C) He.
(D) Ne.
Answer. A

Question. Two electrons occuping the same orbital are distinguished by
(B) azimuthal
(A) principal quantum number. quantum number.
(C) magnetic quantum number.
(D) spin quantum number.
Answer. D

Question. The orientation of an atomic orbital is governed by
(A) spin quantum number.
(C) principal quantum number.
(B) magnetic quantum number.
(D) azimuthal quantum number.
Answer. B

Question. Bohr's model successfully explained the spectrum of
(A) hydrogen molecule only .
(B) hydrogen atom and hydrogen like ions.
(C) all group 1 elements.
(D) all diatomic gases.
Answer. B

Question. Electrons can absorb photon but cannot emit the photon when present in
(A) 2p orbital.
(B) 1s orbital.
(C) 3d orbital.
(D) 4f orbital.
Answer. B

Question. For f-electrons, the orbital angular momentum is
(A) 6h
(B) 2
(C) h √3/π
(D) h
Answer. C

Question. If the Oxygen atom had electronic configuration 1s8, it would have lower energy than that of the normal ground state configuration 1s2 2s2 2p4, because the electrons would be closer to the nucleus. Yet 1s8 is not observed because it violates.
(A) Heisenberg's uncertainity principle
(B) Hund's rule
(C) Pauli exclusion principle
(D) Bohr postulate of stationary theory
Answer. C

Question. All the statements about electron are true except
(A) it is negatively charged particle.
(B) it is a basic constituent of all atoms.
(C) it is a constituent of cathode rays.
(D) the mass of electron is equal to the mass of proton.
Answer. D

Question. The number of orbitals associated of an energy level with n=3 is
(A) 3.
(B) 6.
(C) 9.
(D) 12.
Answer. C

Question. The number of protons, electrons and neutrons in are
(B) 35, 35 and 31 respectively.
(A) 35, 36 and 36 respectively.
(C) 35, 35 and 46 respectively.
(D) 35, 42 and 46 respectively.
Answer. B

Question. The element with electronic configuration 1s2, 2s2,2p6 ,3s2,3p6,3d2 ,4s2, is
(A) scandium.
(B) titanium.
(C) chromium.
(D) vanadium.
Answer. A

Question. Number of electrons having l=1 in a sulphur atom is
(A) 6.
(B) 8.
(C) 10.
(D) 12.
Answer. D

Question. The two d-orbitals, which are directed along the axis, are
(A) dxz & dyz.
(B) dz2 & dyz.
(C) dxz & dxy.
(D) d_z² & d_x²-y²
Answer. D

Question. Correct set of four quantum numbers for the valence electrons of potassium are
(A) n=4, l=0, m=0, s= 1/2.
(B) n=4, l=1, m=0, s= 1/2.
(C) n=4, l=1, m= 1, s= 1/2.
(D) n=4, l=2, m=0, s= 1/2.
Answer. A

Question. If the valence electron of an element has quantum numbers given by, n=4, l=0, m=0, then atomic number of element would be
(A) 11 or 12.
(B) 13 or 14.
(C) 19 or 20.
(D) 21 or 22.
Answer. C

Question. The 4f- sub shell of an atom contains 12 electrons. The maximum number of electrons having same spin are
(A) 5.
(B) 6.
(C) 7.
(D) 10.
Answer. D

Question. Highest paramagnetism is shown by
(A) Cr³⁺.
(B) Fe²⁺.
(C) Cu²⁺.
(D) Mn²⁺.
Answer. B

Question. If the outermost electron of an element has quantum numbers given by n=3, l=0, m=0, then the name of element would be
(A) calcium.
(B) potassium.
(C) sodium.
(D) Aluminium
Answer. C

Question. The probability of finding the electron in the px - orbital is
(A) maximum at the nucleus.
(B) maximum on two opposite sides of the nucleus along x-axis.
(C) maximum on z-axis.
(D) same on all sides around the nucleus.
Answer. B

Question. The total number of electrons present in all the s-orbitals, p-orbitals and d-orbitals of Cu+ are respectively
(A) 6, 12, 10.
(B) 7, 12, 10.
(C) 7, 12, 9.
(D) 7, 11, 10.
Answer. A

Question. In accordance with Aufbau rule, the group number of element with atomic number 48 will be
(A) IA.
(B) IIA.
(C) IIB.
(D) IVA.
Answer. C

Question. Magnetic quantum number signifies
(A) size of orbitals.
(B) shape of orbitals.
(C) orientation of orbitals
(D) nuclear stability.
Answer. C

Question. K, L and M shells of an atom have 2, 8 and 5 electrons respectively. The number of electrons in its p-orbitals is - 
(A) 6
(B) 7
(C) 8
(D) 9
Answer. D

Question. Which of the following is correct electronic configuration of argon ?
(A) 2, 8
(B) 2, 8, 8
(C) 2, 8, 1
(D) 8, 2, 8
Answer. B

Question. The electronic configuration of Cu²⁺ (Z = 29) ion is 
(A) [ Ar ] 3d¹⁰ 4s⁰
(B) [ Ar ] 3d¹⁰ 4s¹
(C) [ Ar ] 3d⁹ 4s⁰
(D) [ Ar ] 3d⁷ 4s²
Answer. C

Question. Isotopes of an element have 
(A) same physical properties
(B) different chemical properties
(C) different no. of neutrons
(D) different atomic number
Answer. C

Question. The electronic configuration of an ion M²⁺ is 2,8,14. If its mass is 56, the number of neutrons in its nucleus is :
(A) 30
(B) 32
(C) 34
(D) 42
Answer. A

Question. Structure of nuclei of three atoms A, B and C are given below -
A has 90 protons and 146 neutrons
B has 92 protons and 146 neutrons
C has 90 protons and 148 neutrons
Based on the above data, which of these atoms are isotopes and which are isobars ?
(A) A and C are isotopes B and C are isobars
(B) A and B are isotopes A and C are isobars
(C) B and C are isobars A and B are isotopes
(D) A and C are isotopes A and B are isobars
Answer. A

Question. Which of the following will have equal number of electrons ?
(A) Cl and Br
(B) Na⁺ and Mg²⁺
(C) Ar and Ne
(D) Mg²⁺ and Ca²⁺
Answer. B

Question. Three elements A, B and C have atomic number Z-1, Z and Z+2 respectively. B is a noble gas. The compound between A and C will be : 
(A) CA₂
(B) CA
(C) C₂A
(D) CA₃
Answer. A

Question. The distribution of electrons in different shells in the element with atomic number 25 is :
(A) 2, 8, 15
(B) 2, 18, 5
(C) 2, 8, 13, 2
(D) 2, 8, 8, 7
Answer. C

Question. When two atoms combine to form molecule then :
(A) energy is released
(B) energy is abosrbed
(C) energy is neither released nor absorbed
(D) energy may either be released or absorbed
Answer. A

Question. The electronic structure of four elements a, b c, d respectively are : 
1s² 1s², 2s², 2p² 1s², 2s², 2p⁵ 1s², 2s², 2p⁶
The tendency to form electrovalent bond will be largest in
(A) a
(B) b
(C) c
(D) d
Answer. C

Question. Which statement is correct about a proton ? 
(A) It is nucleus of deuterium.
(B) it is ionised hydrogen molecule.
(C) it is ionised hydrogen atom.
(D) it is α-particle.
Answer. C

Question. Which of the following statements is incorrect? 
(A) Charges on an electron and proton are equal and opposite.
(B) Neutron have no charge.
(C) Electron and proton have same mass.
(D) Masses of proton and neutron are nearly the same.
Answer. C

Question. Electronic configuration of copper (atomic No. Cu – 29) is : 
(A) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ 4s² 4p¹
(B) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹ 4s¹ 4p¹
(C) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ 4s¹ 4p¹
(D) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹ 4p⁰
Answer. D

Question. Atomic number of which element is 19 ?
(A) Mg
(B) K
(C) Ar
(D) Ca
Answer. B

Question. Which of the following pair is isoelectonic ?
(A) Na⁺, Ar
(B) Mg⁺⁺, Ca⁺⁺
(C) K⁺, Ar
(D) Na⁺, K
Answer. C

Question. False statement for second period elements is-
(A) change in number of electrons produces ions
(B) numbers of protons and electrons are equal in neutral atom
(C) number of neutrons is less than the number of protons in atoms
(D) change in the number of neutrons in atom produces isotopes
Answer. C

Question. Neutronless neutral atom is : 
(A) H
(B) He
(C) Na
(D) K
Answer. A

Question. Neutron was discovered by 
(A) Thomson
(B) Rutherford
(C) Chadwick
(D) Niels Bohr
Answer. C

Question. Which of the following is not a characteristic of a Cathode Rays ?
(A) It has a negative charge.
(B) It deviates in the electric field
(C) It passes through black opaque paper
(D) It travels in straight line.
Answer. C

Question. Which rays are used to diagnose Intestinal cancer ? 
(A) Laser Rays
(B) Cathode Rays
(C) X-Rays
(D) γ Rays
Answer. C

Question. How many times weight of proton is greater than the mass of the electron ? 
(A) 1838
(B) 1836
(C) 1338
(D) 1336
Answer. A

Question. ‘Proton’ is :
(A) Nucleus of Deuterium
(B) Ionised hydrogen molecule
(C) Ionised hydrogen atom
(D) An alpha particle
Answer. C

Question. Arrange of the following consist of one electron, one proton and zero neutron ?
(A) ₁H²
(B) ₁H¹
(C) ₁H³
(D) ₂He⁴
Answer. B

Question. The ascending order of e/m (charge/mass) value for electron (e), proton(p), neutron(n) and alpha(α) particle is 
(A) e, p, n, α
(B) n, p, e, α
(C) n, α, p, e
(D) n, p, α, e
Answer. C

Question. Structure of nuclei of three atoms X,Y and Z are as follows : 
(A) X has 90 Protons and 146 Neutrons. (2) Y has 92 Protons and 146 Neutrons.
(C) Z has 90 Protons and 148 Neutrons.
Which of the following statement is correct based on above data ?
(A) X and Z are isotopes ; Y and Z are isobars.
(B) X and Y are isotopes; X and Z are isobars.
(C) Y and Z are isobars ; X and Z are isobars.
(D) X and Z are isotopes ; X and Y are isobars.
Answer. A

Question. Electron was discovered by...................... 
(A) Chadwick
(B) Rutherford
(C) Thomson
(D) Niel’s Bohr
Answer. C

Question. What are the electronic configurations of Na⁺ and Cl^– ions ?
(A) Na+ = 2, 8, 1 and Cl– = 2, 8, 7
(B) Na+ = 2, 8 and Cl– = 2, 8, 8
(C) Na+ = 2, 8, 2 and Cl– = 2, 8, 6
(D) Na+ = 2, 8 and Cl– = 2, 8, 7
Answer. B

Question. In the helium atom, the number of electrons in L-shell will be : 
(A) 0
(B) 2
(C) 8
(D) 6
Answer. A

Question. The value of ‘X’ in K₂ Al₂ ( SO₄)x. 24H₂O is ……… 
(A) 1
(B) 2
(C) 3
(D) 4
Answer. D

Question. How many orbitals can have the following set of quantum numbers : n = 3, l = 2, m1 = – 2
(A) 1
(B) 8
(C) 2
(D) 4
Answer. A

Question. An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons.
Atomic number of the element is 
(A) 24
(B) 25
(C) 26
(D) 27.
Answer. A

Question. If 1021 molecules of CO₂ are removed from 200 mg of CO₂ sample, then the number of moles of CO₂ left are
(A) 2.88 × 10?3
(B) 4.54 × 10^–3
(C) 1.66 × 10^–3
(D) 1.66 × 10^–2
Answer. C

Question. How many sub-atomic particles are present in an α-particle used in Rutherford’s scattering experiment ?
       No. of       No. of     No. of 
      protons   Neutrons   Electrons
(A)   4              0             0
(B)   2              0             2
(C)   2             2              0
(D)   2             2              1
Answer. C

Question. A certain sample of element Z contains 60% of 69Z and 40% of 71Z. What is the relative atomic mass of element Z in this sample ? 
(A) 69.2
(B) 69.8
(C) 70.0
(D) 70.2
Answer. B

Question. Number of valence electrons in Magnesium is 
(A) 12
(B) 10
(C) 8
(D) 2
Answer. D

Question. Number of which among the following is same in Al+3 and F- ? 
(A) Proton
(B) Neutron
(C) Atomic mass
(D) Electron
Answer. D

Question. Electronic configuration of an atom is 2,8,1. Which of the following elements is similar with it in chemical reactivity ? 
(A) K
(B) Cl
(C) N
(D) Ar.
Answer. A

Question. While attending the physics class on optics a student was taught that light with established wave nature should have particle nature also. Immediately an idea came to the mind of the student that matter with established particle nature should have wave nature also. After completing his studies he published a research paper stating the dual nature of matter and later he was awarded Nobel Prize for his work.
(i) Name the scientist who stated the dual nature of matter.
(ii) Give the mathematical statement of the dual nature of matter.
(iii) Write the type of particles for which this principle is applicable.
(iv) Mention the value associated with this principle.

Question. Guided by Heisenberg’s uncertainty principle and de-Broglie’s theory of dual nature of particles Schrodinger proposed wave equation. To get proper solution of this equation integer called quantum numbers were required.
(i) Name the quantum numbers.
(ii) Write the general values assigned to the quantum numbers.
(iii) Mention the value or values associated with wave equation.

Question. After the discovery of electron and proton Sir J.J. Thomson proposed the plum pudding model of the atom .But this atomic model was abandoned when Rutherford performed the alpha particle scattering experiment.
(i) Name the model of the atom proposed by the Rutherford.
(ii) Mention the main features OF THE ATOMIC MODEL proposed by Rutherford.
(iii) Write the value associated with Rutherford’s model of the atom.

Question. Sukumar, a student of class XI science has learnt to write the electronic configuration of the elements in the chemistry class. Now, He further wanted to know the rules for finding the group numbers. On the next day he discussed his problem with his teacher. The teacher told his the rules for finding the group number. Sukumar, then got satisfied.
(i) What rules were told to Sukumar by his teacher?
(ii) What atom is indicated by the following electronic configuration?
(iii) What values are displayed by Sukumar.

 
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