Question

Difficulty: EasyAtomic Models

Historical developments in atomic physics led to several distinct models of atomic structure. Match each atomic model on the left with its defining structural feature or experimental basis on the right.

  • Thomson's ModelTreats electrons as embedded within a continuous sphere of positive electric charge.
  • Rutherford's ModelProposes a tiny, dense positive nucleus based on large-angle alpha particle scattering.
  • Bohr's ModelPostulates discrete, non-radiating electron orbits with quantized angular momentum.
  • Quantum Mechanical ModelDescribes electron locations using three-dimensional probability distributions (orbitals).

Answer

Thomson's Model matches with embedded electrons in a positive sphere; Rutherford's Model matches with a dense positive nucleus from alpha scattering; Bohr's Model matches with quantized non-radiating orbits; Quantum Mechanical Model matches with electron probability orbitals.
Each historical atomic model is correctly matched to its fundamental feature: Thomson proposed electrons suspended in positive mass; Rutherford used alpha scattering to discover the compact nucleus; Bohr quantized electron orbits to explain spectral lines; and the Quantum Mechanical Model represents electrons via three-dimensional probability orbitals.

Step-by-Step Solution

1
Identify Thomson's contribution
Thomson proposed the 'plum pudding' model where negative electrons are embedded inside a uniform positive charge sphere.
This preceded the discovery of the atomic nucleus.
2
Identify Rutherford's contribution
Rutherford discovered the central positive nucleus through the alpha particle deflection experiment.
Large deflections meant most atomic mass and positive charge concentrated at a tiny core.
3
Identify Bohr's contribution
Bohr added quantum conditions to planetary orbits so electrons remain stable without continuously radiating energy.
Quantized angular momentum explains discrete emission line spectra.
4
Identify the Quantum Mechanical Model contribution
Modern quantum mechanics replaces fixed circular orbits with wave functions and 3D probability clouds (orbitals).
Heisenberg's uncertainty principle rules out precise circular orbits.

Key Concept

Evolution of Atomic Models
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