Part One I › Division I I › Section 111 111

The Structure and Properties of Atoms

Subject Outline

AThe atomic nature of matter
- 1The atom as consisting of the nucleus surrounded by electrons, the arrangement and behaviour of which determine atomic interactions
- 2Early philosophical speculations on the possible atomic nature of matter
- 3The scientific evidence for the existence and the nature of atoms
  - aDevelopments in chemistry
  - bThe development of spectroscopy and the discovery of atomic spectra
  - cThe discovery of the electron as a particle and as a component of all matter
  - dThe discovery of X rays
  - eThe discovery of the radioactive transformation of one element into another
  - fThe Brownian movement of suspended particles
  - gThe development of mass spectrometry
  - hThe development of scattering and resonance studies with atomic and molecular beams
- 4Models of atomic structure
  - aThe Rutherford model of the atom
  - bThe Bohr-Sommerfeld model
  - cThe wave-mechanical theory of the electronic structure of the atom
BAtomic weights
- 1Variations in atomic weight as a result of variations in isotopic composition
- 2Significance of atomic weights in chemistry
- 3Atomic weight scales
- 4Methods used for determining atomic weights: chemical methods, physical methods
CAtomic spectra and the electronic structures of the atom
- 1Atomic spectra: their significance and interpretation
  - aThe spectrum of the hydrogen atom
  - bThe emission spectra of singly and multiply ionized atoms
  - cAtomic absorption spectra
  - dThe effects of magnetic fields and the effects of electric fields on atomic spectra
  - eIntensities, isotope shifts, and fine and hyperfine structures of atomic spectral lines as related to atomic structure
- 2Theories of the origin of atomic spectra in quantized electronic transitions: the classical Bohr theory, wave-mechanical interpretations
DX rays and atomic structure
- 1General X-ray phenomena
- 2The theory of X rays and their spectra
  - aThe structure of the atom as related to the emission of characteristic X rays, absorption edges, fluorescence yield, mesic atoms
  - bContinuous X rays and bremsstrahlung; i.e., the radiation produced by the sudden retardation of a fast-moving charged particle in an intense electrical field
- 3Detection and measurement of X rays
- 4Applications of X rays in biological, medical, industrial, and scientific fields [see 423.B. and 723.G.8.]
- 5Diffraction of X rays by crystals [see 125.A.2.]
EThe concept of antimatter
- 1General properties of antimatter
- 2Production of antiparticles in high-energy collisions
- 3Invariance of the laws of physics under charge conjugation, an operation in relativistic mechanics that transforms every particle into its antiparticle
- 4Speculations about the possible existence and role of antimatter in the universe
FThe fundamental physical constants: dimensional and dimensionless constants
- 1Measurement of the physical constants
- 2Interrelationships among the constants