Class 11 Atomic Structure MCQs with Answer

We have compiled the MCQ Questions for Class 11 Chemistry MCQs with Answers PDF free download covering the entire syllabus. Practice MCQ Questions for Class 11 Chemistry with Answers on a daily basis and score well in exams. Refer to the Structure of Atom Class 11 MCQs Questions with Answers here along with a detailed explanation.

Class 11 Chemistry Atomic Structure MCQs with Answer

Q1. For the electrons of oxygen atom, which of the following statements is correct?

1. Zeff for an electron in a 2s orbital is the same as Z for an electron in a 2p orbital.
2. An electron in the 2s orbital has the same energy as an electron in the 2p orbital.
3. Zeff for an electron in 1s orbital is the same as Z for an electron in a 2s orbital LED.
4. The two electrons present in the 2s orbital have spin quantum numbers m, but of opposite sign.

Q2. Which of the following statements is/ are correct regarding Rutherford scattering experiment?

1. Most of the A-particles passed through the gold foil remain undeflected.
2. A small fraction of the Q-particles was deflected by small angles.
3. A very few a-particles in bounced back, i.e. were deflected by nearly 180°.
4. All of the above.

Q3. If travelling at same speeds, which of the following matter waves have the shortest wavelength?

1. Electron.
2. Alpha particle (He²⁺ )
3. Neutron.
4. Proton.

Q4. Which of the following statements concerning the quantum numbers are correct?

1. Angular quantum number determines the three dimensional shape of the orbital.
2. The principal quantum number determines the orientation and energy of the orbital.
3. Magnetic quantum number determines the size of the orbital.
4. Spin quantum number of an electron determines the orientation of the spin of electron relative to the
   chosen axis.

Q5. The ration of de Broglie wavelengths of a deuterium atom to that of a-particles, when the velocity of the former
is 5 times greater than of latter is:

1. 4
2. 0.2
3. 2
4. 0.4

Q6. Which of the following statement is not correct regarding Bohr’s model of hydrogen atom?

1. Energy of the electrons in the orbit is quantized.
2. The electron in the orbit nearest to the nucleus has the lowest energy.
3. Electrons revolve in different orbits around the nucleus.
4. The position and velocity of the electrons in the orbit cannot be determined simultaneously.

Q7. Which of the following statements about the electron is incorrect?

1. It is a negatively charged particle.
2. The mass of electron is equal to the mass of neutron.
3. It is a basic constituent of all atoms.
4. It is a constituent of cathode rays.

Q8. For the electrons of oxygen atom, which of the following statements is correct?

1. Z_eff for an electron in a 2s orbital is the same as Z_eff for an electron in a 2p orbital.
2. An electron in the 2s orbital has the same energy as an electron in the 2p orbital.
3. Z_eff for an electron in 1s orbital is the same as Z_eff for an electron in a 2s orbital.
4. The two electrons present in the 2s orbital have spin quantum numbers m_s but of opposite sign.

Q9. Major development(s) responsible for the formulation of Bohr’s model of atom were:

1. Dual character of the electromagnetic radiation.
2. Experimental results regarding atomic spectra which can be explained only by assuming quantized
   electronic energy levels in atoms.
3. Both (a) and (b).
4. None of the above.

Q10. The only series of lines appear in the visible region of the electromagnetic spectrum of hydrogen is:

1. Lyman series.
2. Balmer series.
3. Paschen series.
4. Pfund series.

Q11. The spectrum of radiation emitted by a substance after absorbing energy is called:

1. Absorption spectrum.
2. Emission spectrum.
3. White light spectrum.
4. None of the above.

Q12. The atomic numbers of elements X, Y and Z are 19, 21 and 25 respectively. The number of electrons present in
the M-shell of these elements follow the order:

1. Z > X > Y
2. X > Y > Z
3. Z > Y > X
4. Y > Z > X

Q13. According to the electromagnetic theory of Maxwell, which one is correct?

1. Charged particles when accelerated should emit electromagnetic radiation.
2. Charged particles when accelerated should absorb electromagnetic radiation.
3. Charged particles when retarted should emit EMR.
4. None of the above.

Q14. The series of lines appearing in UV region of electromagnetic spectrum of hydrogen is called:

1. Bracket series.
2. Pfund series.
3. Lyman series.
4. Paschen series.

Q15. Which of the following conclusions could not be derived from Rutherford’s -particle scattering experiement?

1. Most of the space in the atom is empty.
2. The radius of the atom is about 10 m while that of nucleus is 10-¹⁵ m.
3. Electrons move in a circular path of fixed energy called orbits.
4. Electrons and the nucleus are held together by electrostatic forces of attraction.

Q16. Orbital angular momentum depends on _.

1. l
2. n and l
3. n and m
4. m and s

Q17. Chlorine exists in two isotopic forms, Cl-37 and Cl-35 but its atomic mass is 35.5. This indicates the ratio of Cl-37
and Cl-35 is approximately:

1. 1 : 2.
2. 1 : 1.
3. 1 : 3.
4. 3 : 1.

Q18. Two atoms are said to be isobars if:

1. They have same atomic number but different mass number.
2. They have same number of electrons but different number of neutrons.
3. They have same number of neutrons but different number of electrons.
4. Sum of the number of protons and neutrons is same but the number of protons is different.

Q19. Pairing of electrons in the orbitals belonging to the same subshell (p, d or f) does not take place until each orbital
belonging to that subshell is singly occupied. This is called:

1. Hund’s rule of maximum multiplicity.
2. Pauli’s exclusion principle.
3. Aufbau principle.
4. None of the above.

Q20. The phenomenon of splitting of spectral lines under the influence of the electric field is called:

1. Stark effect.
2. Photoelectric effect.
3. Zeeman effect.
4. Electromagnetic effect.

Q21. Aufbau principle does not give the correct arrangement of filling up of the atomic orbitals in:

1. Cu and Zn
2. Co and Zn
3. Mn and Cr
4. Cu and Cr

Q22

Q22. Which of the following statement is not correct about the characteristics of cathode rays?

1. They start from the cathode and move towards the anode.
2. They travel in straight line in the absence of an external electrical or magnetic field.
3. Characteristics of cathode rays do not depend upon the material of electrodes in cathode ray tube.
4. Characteristics of cathode rays depend upon the nature of gas present in the cathode ray tube.

Q23. Which of the following properties of atom could be explained correctly by Thomson model of atom?

1. Overall neutrality of atom.
2. Spectra of hydrogen atom.
3. Position of electrons, protons and neutrons in atom.
4. Stability of atom.

Q24. Pauli exclusion principle states that:

1. No two electrons in an atom can have the same set of four quantum numbers.
2. Only two electrons may exist in the same orbital and these electrons must have opposite spin.
3. Both (a) and (b).
4. None of the above

Q25. A ray of white light is spread out into a series of coloured bands of visible light are called:

1. Visible band.
2. Spectrum.
3. Electronic spectrum.
4. None of these.

Q26. Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons?

1. Pauli’s exclusion principle.
2. Heisenberg’s uncertainty principle.
3. Hund’s rule of maximum multiplicity.
4. Aufbau principle.

Q27. The probability density plots of 1s and 2s orbitals are given in figure.
The density of dots in a region represents the probability density of finding electrons in the region.
On the basis of above diagram which of the following statements is incorrect?

1. 1s and 2s orbitals are spherical in shape.
2. The probability of finding the electron is maximum near the nucleus.
3. The probability of finding the electron at a given distance is equal in all directions.
4. The probability density of electrons for 2s orbital decreases uniformly as distance from the nucleus
   increases.

Q28. On bombarding a beam of a-particles on the atom of the gold sheet, a few particles get deflected whereas most
of them go straight and remains undeflected. This is due to:

1. The nucleus occupy much smaller volume as compared to the volume of atom.
2. The force of repulsion on fast moving a-particles is very small.
3. The neutrons in the nucleus do not have any effect on a-particles.
4. The force of attraction on a-particles by the oppositely charged electron is not sufficient.

Q30. The number of radial nodes for 3p orbital is __.

1. 3
2. 4
3. 2
4. 1