Class 11 Chemistry

1. Who discovered the electron?

• A. J.J. Thomson
• B. Ernest Rutherford
• C. James Chadwick
• D. John Dalton

2. The neutron was discovered by:

• A. James Chadwick
• B. J.J. Thomson
• C. Ernest Rutherford
• D. Niels Bohr

3. What is the charge-to-mass ratio (e/m) of an electron?

• A. 1.758820 × 10¹¹ C/kg
• B. 1.602 × 10⁻¹⁹ C/kg
• C. 9.109 × 10⁻³¹ C/kg
• D. 1.758820 × 10⁸ C/kg

4. Rutherford's alpha-particle scattering experiment led to the discovery of the:

• A. Atomic nucleus
• B. Electron
• C. Proton
• D. Neutron

5. The principal quantum number (n) determines the:

• A. Size and energy of the orbital
• B. Shape of the orbital
• C. Spatial orientation of the orbital
• D. Spin orientation of the electron

6. The shape of a p-orbital is:

• A. Dumb-bell
• B. Spherical
• C. Double dumb-bell
• D. Complex

7. How many subshells are present in the shell with principal quantum number n = 3?

• A. 3
• B. 2
• C. 4
• D. 9

8. What is the maximum number of electrons that can be accommodated in a d-subshell?

• A. 10
• B. 6
• C. 2
• D. 14

9. Which rule states that no two electrons in an atom can have the same set of four quantum numbers?

• A. Pauli Exclusion Principle
• B. Aufbau Principle
• C. Hund's Rule of Maximum Multiplicity
• D. Heisenberg Uncertainty Principle

10. According to the Aufbau Principle, orbitals are filled in order of their:

• A. Increasing energy
• B. Decreasing energy
• C. Increasing size
• D. Decreasing size

11. What is the total number of orbitals in a shell with principal quantum number n?

• A. n²
• B. 2n²
• C. 2n
• D. n + 1

12. De Broglie wavelength of a particle is given by the expression:

• A. λ = h / mv
• B. λ = mv / h
• C. λ = h / m
• D. λ = h / v

13. Which quantum number specifies the spatial orientation of an orbital?

• A. Magnetic quantum number (mₗ)
• B. Principal quantum number (n)
• C. Azimuthal quantum number (l)
• D. Spin quantum number (mₛ)

14. Isobars are atoms having the same:

• A. Mass number but different atomic numbers
• B. Atomic number but different mass numbers
• C. Number of neutrons
• D. Number of protons

15. The correct electronic configuration of Chromium (Cr, Z = 24) is:

• A. [Ar] 3d⁵ 4s¹
• B. [Ar] 3d⁴ 4s²
• C. [Ar] 3d⁶ 4s⁰
• D. [Ar] 3d³ 4s² 4p¹

16. What is the value of Azimuthal quantum number (l) for a d-subshell?

• A. 2
• B. 0
• C. 1
• D. 3

17. Heisenberg's Uncertainty Principle is mathematically stated as:

• A. Δx · Δp ≥ h / (4π)
• B. Δx · Δp = h / (2π)
• C. Δx · Δp ≤ h / (4π)
• D. Δx · Δv ≥ h / (2π)

18. The line spectrum of hydrogen was first successfully explained by:

• A. Niels Bohr
• B. J.J. Thomson
• C. Ernest Rutherford
• D. Erwin Schrödinger

19. Which spectral series of hydrogen atom lies in the visible region?

• A. Balmer series
• B. Lyman series
• C. Paschen series
• D. Brackett series

20. The maximum number of electrons in a main shell is given by:

• A. 2n²
• B. n²
• C. 2n + 1
• D. 4l + 2

21. Isotopes are atoms of the same element having:

• A. Same atomic number but different mass numbers
• B. Same mass number but different atomic numbers
• C. Same number of neutrons
• D. Different number of protons

22. The energy of a photon of frequency ν is given by Planck's equation:

• A. E = hν
• B. E = mc²
• C. E = h / ν
• D. E = ν / h

23. Electronic configuration of Copper (Cu, Z = 29) is:

• A. [Ar] 3d¹⁰ 4s¹
• B. [Ar] 3d⁹ 4s²
• C. [Ar] 3d⁸ 4s²
• D. [Ar] 3d¹⁰ 4s²

24. What is the number of radial nodes for a 3p orbital?

• A. 1
• B. 2
• C. 0
• D. 3

25. Species having the same number of electrons are called:

• A. Isoelectronic species
• B. Isotopes
• C. Isobars
• D. Isotones

26. Which orbital has a spherical shape?

• A. s-orbital
• B. p-orbital
• C. d-orbital
• D. f-orbital

27. Which rule states that electron pairing in degenerate orbitals does not take place until each orbital is singly occupied?

• A. Hund's Rule
• B. Pauli Exclusion Principle
• C. Aufbau Principle
• D. Heisenberg Principle

28. Photoelectric effect was successfully explained by Albert Einstein using:

• A. Quantum theory of light
• B. Wave theory of light
• C. Classical electrodynamics
• D. Rutherford model

29. The value of Planck's constant (h) is:

• A. 6.626 × 10⁻³⁴ J·s
• B. 6.022 × 10²³ J·s
• C. 1.602 × 10⁻¹⁹ J·s
• D. 9.109 × 10⁻³¹ J·s

30. What is the maximum number of electrons in an orbital?

• A. 2
• B. 6
• C. 10
• D. 14