E.1 Structure of the atom

• Geiger-Marsden-Rutherford experiment and the discovery of the nucleus.

• Use nuclear notation: A = nucleon number, Z = proton number, X = element symbol.

• Emission and absorption spectra provide evidence for discrete atomic energy levels.

• Photons are emitted/absorbed during transitions between atomic energy levels.

• Photon energy in atomic transition: E=hf.

• Use emission and absorption spectra to infer chemical composition.

• Nuclear radius scales with nucleon number: R=R0 A^(1/3); implies near-constant density.

• Relationship implies approximately constant nuclear density.

• Deviations from Rutherford scattering at high energies.

• Use energy conservation for distance of closest approach in head-on scattering.

• Bohr hydrogen energy levels: E=-13.6/n^2 eV.

• Bohr quantization: angular momentum mvr = nh/(2π).