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Rutherford model limits
Intermediate
Classical orbiting electrons would spiral into the nucleus.
A classical electron orbiting a nucleus would radiate and spiral in within 10⁻¹¹ s, and would give a continuous spectrum. Atoms are stable and emit lines, which classical physics can't explain.
Led directly to Bohr's quantisation.
Fails because it ignores quantum effects.
In more detail
The Rutherford model could not explain why atoms are stable, since an orbiting electron should radiate energy and spiral into the nucleus. It also could not explain line spectra.
Real-world uses
- These failures motivated the Bohr model and quantum mechanics.
- They show why a model must explain all available evidence.
- Physicists explained that a classical electron orbiting a nucleus would radiate energy and collapse, which motivated the Bohr model.
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Frequently asked questions
What is the main problem?
Classical electromagnetism predicts that an accelerating electron radiates and collapses.
How was it fixed?
By Bohr's quantised orbits and later by quantum mechanics.
Why does an orbiting electron lose energy classically?
An accelerating charge radiates electromagnetic waves, so a classical electron would lose energy and spiral into the nucleus.
Related topics in Atomic & Nuclear Physics
Thomson's plum pudding · Rutherford's scattering experiment · Bohr model · Bohr's postulates · Radius of Bohr orbit