1. September 22, 1998 Models of the Atom - Orbits to Clouds
Bohr:1. Newton’s 2nd Law… electric force
causes electron to move at velocity
v at radius r. k e2/r2 = m v2/r
2. Energy is kinetic and electric.
E = 1/2 m v2 - k e2/r
3. Angular motion is “quantized”.
L = m v r = n h/ 2 p
4. Photon equals energy difference
Ef - Ei = h f

2. September 22, 1998 2 DeBroglie (1914)
But what if the electron is wave of
wavelength l such that m v = h / l.
Shroedinger Wave Equation (1926):
Energy = Kinetic + Electric
When solved, the results gave conditions

3. September 22, 1998 3 Each electron has 4 “Quantum Numbers”:
n = 1, 2, 3, 4,… gives orbit like Bohr
l = 0, 1, 2,… n-1… gives L
ml = - l…0... l … gives vertical
part of L
ms = +1/2, -1/2
And: No two electrons can have same set.

4. September 22, 1998 4 Application: n = 1 1 0 0 +1/2 1 0 0 -1/2
Only two electrons allowed in first orbit.
n = / /2
/ /2
/ /2
/ /2
Eight electrons allowed in second orbit

5. September 22, 1998 5 Clouds of the Hydrogen Atom…(film/computer)
Atom in a Box
Spectrum of Hydrogen Atom… transitions
from higher levels to lower levels…
Applying the Hydrogen quantum levels to other
atoms… the periodic table (film)

6. September 22, 1998 6 Applications
Atoms and Isotopes (Stable vs Unstable)
Fission, Fusion, Radioactivity
Molecules: H2 CH4 H2O
Sharing electrons
Chemical Reactions
Conservation of Atoms, Energy
Solids
Crystal Structure and Uses