Chapter 5:
Periodicity and Atomic Structure

In this chapter you will get a modern understanding of the atom.  Much of them came from an understanding of how light interacts with matter.  First we will explore the nature of light, followed by its interaction with matter, and then a new description of electrons and electron arrangement around nuclei.  

Intro to Light:  For these links get a sense of some properties of light.

  • EM spectrum:  visible light is small part of the entire electromag. spectrum
  • Prism A prisms bends light of different wavelengths to different degrees, allowing "white" light to be separated into its components
  • Index of Refraction Different media bend light differing amounts.
  • Diffraction Grating 2 | CD - diffraction grating Gratings (numerous slits etched in a transmitting or reflecting surface) can also separate light into its component wavelengths, much like a prism.

Intro to Waves: Types and Properties

  • TYPES OF WAVES The water and EM waves below are example of transverse waves - the disturbance is perpdenicular to the direction of propagation of the wave
    • water waves You've done this a a kid.  Circular water waves emanate from the point of disturbance.  Note the propagating lighter/darker regions.  These reflect the crest/trough of the wave (or depending how the movie was made, the trough/crest.
    • electromagnetic waves : light as two mutually perpendicular waves - one an oscillation in the electric field, and one in the magnetic field
  • PROPERTIES OF WAVES I:  What do waves do?  They reflect, refract (see above) and diffract (bend around corners).  When to waves meet, they add to each other in ways that produce constructive interference - when peaks arrive simultaneously, or destructive interference (when a peak and trough arrive simultaneously).  When the combine or "superimpose" they produce an interference or diffraction pattern.  The links below demonstrate these ideas.
    • Wave Reflection, Fixed End
    • Wave Reflection, Open End
    • Superposition of Waves  :   vTwo sinusoidal waves approach and superimpose (through simple addition of the wave) to form a new resultant wave. 
    • Adding Waves the top two waves can be varied by dragging the balls to produce a new wave form (lower left). Again constructive and destructive interference results in a new wave which is simply the superposition (addition) of the two waves.
    • Two Water Waves Interferring compared to the single water wave above, you will see two water waves superimposing.  you should see rays emanating  from the combined waves showing where the combined waves destructively interfered to produce little observable trough and peaks and rays with constructive interference.  This is also seen in the Two Slit link below
    • Wave Interference 1 Another example
    • Wave Interference 2 Another example
    • Wave Interference 3 Another example
    • Two slit interference This is a pictorial representation that shows the same rays of destructie (-) and constructive (+) interference see in the Water Waves above.   Think of the purple circles as the peak of the waves.
    • Laser through single slit:  Diffraction Demo
      - if slit infinitesimal point, light passing through  emanate in a cone-shaped volume, as if light emitted in all directions through slit (no  diffraction pattern ). 
      - If slit is  very wide, there is no diffractions and light goes straight toward detector. 
      - If the slit width is similar to wavelength of life, get diffraction pattern as if multiple point "slits" existed
    • Another two slit demo An animation of light passing through slits, analagous to the Two Water Wave experiment
    • NaCl Jmol  | X Ray Crystallography 

Classical Physics and the Demise of the planetary  model

Wave Nature of Matter:  Quantum Theory

Quantum Theory and Electronic Structure


  • Quantum Behavior of C70.  Science. 292. pg 1471 (2001)
  • Electronics vs Spintronics:  Nature 411, pg 747 (2001)
  • The Fog That Was Not (Femtosecond resolution and uncertainty) Nature, 412,pg 279 (2001)
  • Zeilinger.  The quantum centennial:  One hundred years ago, a simple concept changed our world view forever. Nature. 408, pg 639 (2000)
  • Schrodiner's Cat is out of the Hat.  Science. 290. pg 720, 773 (2000)