Chemistry Atomic Structure BUMHS 2022
PMDC Verified Question 57 of 95
Which concept was introduced by the scientist Bohr?
A
Energy levels
B
Orbitals
C
Sub-orbits
D
Sub-energy levels
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Energy levels
Concept: Niels Bohr revolutionized atomic theory by introducing quantization to classical planetary models.

Formula: $$ mvr = \frac{nh}{2\pi} $$

Solution:
  • Prior to Bohr, Rutherford's model couldn't explain why orbiting electrons didn't spiral into the nucleus due to continuous energy radiation.
  • Bohr proposed that electrons move in fixed, circular orbits (shells) around the nucleus without radiating energy.
  • He defined these stationary states as specific "energy levels" (K, L, M, etc.).


Why other options are incorrect: The concept of 3D "orbitals" and "sub-energy levels" (subshells) was developed later by quantum mechanics pioneers like Schrödinger and Heisenberg.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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