Unit 1: Atomic Structure — Online MCQ Test
CHEMISTRY · CLASS 11 INTERMEDIATE 1 YEAR · Telangana State Board
Practice Unit 1: Atomic Structure with a free chapter-wise online MCQ test.
This chapter covers: This chapter covers atomic models dual nature of matter de Broglie relationship Heisenberg uncertainty principle quantum numbers and orbitals. Students master Aufbau principle Paul....
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Unit 1: Atomic Structure — Important Questions & Answers
Who proposed the planetary model of the atom with electrons revolving around a small, dense nucleus?
- A. J. J. Thomson
- B. Ernest Rutherford
- C. Niels Bohr
- D. Louis de Broglie
Answer: B. Ernest Rutherford
Rutherford proposed the nuclear model of the atom based on the alpha-particle scattering experiment. It placed the positive charge and most of the mass in a tiny nucleus.
Rutherford proposed the nuclear model of the atom based on the alpha-particle scattering experiment. It placed the positive charge and most of the mass in a tiny nucleus.
The de Broglie wavelength of a particle is given by which expression?
- A. λ = h / mv
- B. λ = mv / h
- C. λ = h / m
- D. λ = hν / v
Answer: A. λ = h / mv
According to de Broglie, a moving particle has wave nature and its wavelength is λ = h/p = h/mv.
According to de Broglie, a moving particle has wave nature and its wavelength is λ = h/p = h/mv.
For an electron in the 3p subshell, what are the possible values of the azimuthal quantum number (l)?
- A. 0 only
- B. 1 only
- C. 2 only
- D. 0, 1, and 2
Answer: B. 1 only
For a p-subshell, the azimuthal quantum number is always l = 1, regardless of the principal quantum number.
For a p-subshell, the azimuthal quantum number is always l = 1, regardless of the principal quantum number.
Which statement best explains why the Bohr model fails for multi-electron atoms?
- A. Electrons do not have mass
- B. Electrons behave only like particles
- C. It cannot account for electron-electron interactions and wave nature
- D. Nucleus does not exist in atoms
Answer: C. It cannot account for electron-electron interactions and wave nature
The Bohr model works well only for hydrogen-like species. It does not explain the behavior of multi-electron atoms because it ignores electron-electron repulsion and quantum mechanical nature of electrons.
The Bohr model works well only for hydrogen-like species. It does not explain the behavior of multi-electron atoms because it ignores electron-electron repulsion and quantum mechanical nature of electrons.
Which statement is correct about the magnetic quantum number for a p-subshell?
- A. It has only one value, 0
- B. It can take values -1, 0, +1
- C. It can take values 0 and 1 only
- D. It is always equal to the principal quantum number
Answer: B. It can take values -1, 0, +1
For a p-subshell, l = 1, so the magnetic quantum number m can be −1, 0, or +1. These represent the three p-orbitals.
For a p-subshell, l = 1, so the magnetic quantum number m can be −1, 0, or +1. These represent the three p-orbitals.