What you’ll learn11 learning objectivesChoose one objective for a focused lesson, or study the complete topic.—E.1.1—Rutherford experiment• Geiger-Marsden-Rutherford experiment and the discovery of the nucleus.Syllabus objective—E.1.2—Nuclear notation• Use nuclear notation: A = nucleon number, Z = proton number, X = element symbol.Syllabus objective—E.1.3—Atomic energy levels• Emission and absorption spectra provide evidence for discrete atomic energy levels.Syllabus objective—E.1.4—Atomic transitions• Photons are emitted/absorbed during transitions between atomic energy levels.Syllabus objective—E.1.5—Photon energy• Photon energy in atomic transition: E=hf.Syllabus objective—E.1.6—Spectra and composition• Use emission and absorption spectra to infer chemical composition.Syllabus objective—E.1.7 (HL)—Nuclear radius• Nuclear radius scales with nucleon number: R=R0 A^(1/3); implies near-constant density.• Relationship implies approximately constant nuclear density.Syllabus objective—E.1.8 (HL)—High-energy scattering deviations• Deviations from Rutherford scattering at high energies.Syllabus objective—E.1.9 (HL)—Closest approach• Use energy conservation for distance of closest approach in head-on scattering.Syllabus objective—E.1.10 (HL)—Bohr hydrogen levels• Bohr hydrogen energy levels: E=-13.6/n^2 eV.Syllabus objective—E.1.11 (HL)—Bohr angular momentum• Bohr quantization: angular momentum mvr = nh/(2π).Syllabus objective