Structure of Atom: Quantum Model

50 lessons, pages 1531–1580.

  1. Why Atomic Structure Needed a New Model — From classical expectations to quantized atomic evidence
  2. Electromagnetic Radiation — Wavelength, frequency, speed and electromagnetic energy
  3. The Electromagnetic Spectrum — Ordering radiation by wavelength, frequency and energy
  4. Blackbody Radiation and Quantization — Why continuous classical energy exchange failed
  5. Photons and the Photoelectric Effect — Threshold frequency and photon energy
  6. Atomic Line Spectra — Discrete emission and absorption wavelengths
  7. Hydrogen Spectrum and the Rydberg Relation — Spectral series from hydrogen energy-level changes
  8. Bohr Model of Hydrogen — Quantized orbits as an early one-electron model
  9. Bohr Energies and Spectral Transitions — Photon energies from differences between allowed levels
  10. Limits of the Bohr Model — Why fixed classical orbits cannot describe general atoms
  11. Matter Waves and de Broglie Wavelength — Wave behavior associated with moving particles
  12. Electron Diffraction — Experimental evidence for electron wave behavior
  13. The Uncertainty Principle — Limits on simultaneous position and momentum knowledge
  14. Wavefunctions and Probability — Interpreting electron probability density
  15. The Schrödinger Description of Hydrogen — Allowed states from a wave equation
  16. Atomic Orbitals Rather Than Orbits — Probability regions instead of electron paths
  17. Principal Quantum Number — Shell number, allowed values and orbital extent
  18. Angular-Momentum Quantum Number — Subshell labels and allowed l values
  19. Magnetic Quantum Number — Counting orbital orientations within a subshell
  20. Electron Spin Quantum Number — The two allowed spin projections
  21. Allowed Quantum-Number Sets — Checking n, l, m_l and m_s together
  22. Shells, Subshells and Orbitals — Hierarchy and capacities from quantum-number rules
  23. The Shape of s Orbitals — Spherical probability distributions and radial variation
  24. The Shape of p Orbitals — Directional lobes and nodal planes
  25. The Shape of d Orbitals — Five orbital orientations and common visual forms
  26. Radial Nodes and Angular Nodes — Zero-probability surfaces in hydrogen-like orbitals
  27. Orbital Size and Penetration — How electron density approaches the nucleus
  28. Hydrogen-Like Ions — One-electron energies and nuclear-charge dependence
  29. Multi-Electron Atom Energies — Shielding and electron repulsion break hydrogen degeneracy
  30. Effective Nuclear Charge — Nuclear attraction screened by other electrons
  31. Aufbau Filling Principle — Building ground-state configurations from lower-energy orbitals
  32. Pauli Exclusion Principle — Unique four-number states and two electrons per orbital
  33. Hund's Rule and Degenerate Orbitals — Unpaired parallel spins before orbital pairing
  34. Orbital Box Diagrams — Representing occupancies and spin arrows
  35. Writing Electron Configurations — Subshell notation for neutral ground-state atoms
  36. Noble-Gas Shorthand — Condensing configurations using a preceding closed shell
  37. Electron Configurations Across Period Two — Filling 2s and 2p from lithium to neon
  38. Electron Configurations Across Period Three — Filling 3s and 3p from sodium to argon
  39. The 4s and 3d Filling Order — Energy ordering and the start of transition series
  40. Chromium and Copper Exceptions — Observed configurations beyond a simple Aufbau list
  41. Other Configuration Exceptions — Limits of a fixed subshell-order mnemonic
  42. Electron Configurations of Cations — Removing electrons from the outermost principal shell
  43. Electron Configurations of Anions — Adding electrons to available valence orbitals
  44. Isoelectronic Species — Different atoms and ions with the same electron count
  45. Valence and Core Electrons — Separating chemically accessible electrons from inner shells
  46. Quantum Model and Periodic Blocks — Relating s, p, d and f blocks to configuration
  47. Paramagnetism and Unpaired Electrons — Magnetic response as a configuration clue
  48. Excited States and Electron Transitions — Configurations above the ground state and emitted light
  49. Quantum-Model Mixed Problems — Integrating spectra, quantum numbers and configurations
  50. Structure of Atom: Quantum Model Review — Connecting experimental evidence to orbital structure