ConceptModern Physics
← All conceptsAtomic structure & spectra
Rutherford gold-foil/α-scattering (small dense nucleus, refutes plum-pudding), Bohr energy levels, photon emission/absorption Ephoton=Ehigh-Elow, number of spectral lines from level n = n(n-1)/2
11 ways this goes wrong. Each one is a named misconception the questions are built to catch.
- Bigger jump, lower frequencyAssociates a larger energy-level transition with a lower-frequency photon, reversing E=hf.→
- Emission/absorption swappedHas the atom absorb a photon when dropping to a lower level (or emit when rising), reversing the transition.→
- Energy levels continuousTreats atomic energy levels as a continuous range rather than discrete quantized states.→
- Level energy sign ignoredIgnores the negative sign of bound-state energies, mishandling which transition is larger.→
- Model attribution swappedCredits the wrong scientist or experiment for a model (e.g. Bohr for the gold-foil scattering, or Thomson for quantized energy levels).→
- Most alphas deflected stronglyClaims a large fraction of α particles bounced back in the gold-foil experiment, rather than the rare large-angle scattering that revealed a tiny dense nucleus.→
- Orbiting electron radiates continuouslyBelieves a Bohr-orbit electron continuously emits radiation, contradicting stable stationary states.→
- Photon energy as level valueSets the photon energy equal to a single level's energy rather than the difference between two levels.→
- Scattering supports plum-puddingReads the gold-foil results as confirming the plum-pudding model instead of refuting it in favor of a concentrated nucleus.→
- Spectral line positions differExpects emission and absorption lines of the same element at different wavelengths.→
- Spectral-line count uses nCounts the number of possible spectral lines from level n as n (or n-1) instead of n(n-1)/2 distinct transitions.→
