Home > Uncategorized > Introduction to Solid State Chemistry Lecture 5

Introduction to Solid State Chemistry Lecture 5

Today’s lecture is 52 minutes long.

A moving electron has KE = 1/2 mv2. It can increase the energy level of something it hits. The promoted electon will fall back down and give the energy off again by an emitted photon. These photons lead to the lines in the spectrum.

dE = (-kZ^2/hc)(1/nf2 – 1/ni2)
nf = 2, z=1 for the Balmer series. ni = 3,4,5…

violet, blue, green, yellow, orange. The visible spectrum is 400-700 nm. 2-3 eV.

The master equation is that v = RZ^2(1/nf2 – 1/ni2) for all one electron atom systems. This is the Rydberg equation. R = 1.1×10^7 1/m.

Bohr Postulates for Hydrogen Atom:
1) Rutherford atom is OK
2) Classical EM no good fro orbiting electrons
3) Newtonian mechanics does apply
4) E electron=E kinetic + E potential
5) Electon energy is quantized by L = nh/2pi for n=1 2 3…
6) Plank Einstein relation applies to electron transitions:
dE = hf

Ionization Energy: Hg(g)=Hg+ + e-

Bohr model cannot explain doublets, nor line splitting in magnetic/electric fields.

Sommerfeld puts a patch on the Bohr model by making electron orbits elliptical. l=0 is circular, l=1 is elliptical, l=2 is more complex.

There are four quantum numbers:

n principal SIZE: 1 2 3 4 5 …

l orbital SHAPE: o, 1, 2…n-1

m magnetic ORIENTATION
l, l-1, 0, -l

SPIN +1/2, -1/2

The circle is a degenerate form of the elipse by Sommerfeld. The symposium picture negative distortation.

The Hindenburg was full of hydrogen. Built in Germany by Zeppelin. 135 ft in diameter by 804 ft long, 7 million cu ft gas giving 112 tons of useful lift. Did not explode! You need one mole of O2 per mole of H2. That wasn’t there. 2.5 days to Europe from Manhattan. 10 transatlantic flights. Dock at Emprire State Building, on top there are moorings. Winds too strong.

SSOS size shape orientation spin

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