The hydrogen atom Energy is measured in eV, or electron volts Light (photon) is electromagnetic...
-
date post
20-Dec-2015 -
Category
Documents
-
view
215 -
download
2
Transcript of The hydrogen atom Energy is measured in eV, or electron volts Light (photon) is electromagnetic...
The hydrogen atom
Energy is measured in eV, or electron volts
Light (photon) is electromagnetic energy
Since only permitted electron orbits (energies), there are only permitted photon energies that interact with the atom.
The photon energy equals the energy difference of the electron orbits
(not shown)
(true colors)
Energy = 12.8 – 10.2 = 2.6 eV
n=1
n=3
n=2
Energy Increasing
Lyman
Balmer
Paschen
Balmer Series
Blackbody Radiation
max = 3,000,000
T nanometer
Etotal = constant x T 4 J/s/m2
Etotal = area under BB curve
T = absolute temperature
Absolute temperature measures the internal kinetic energy of an object. This is the energy from all the motions of the atoms.
Absolute Temperature
Units = Kelvins
Measures kinetic energy (motion and/or speed) of particles in a gas, solid, or a liquid
Shown below is a gas …
coolerhotter
Stars have absorption spectra.
Stellar spectrum showing hydrogen absorption.
Ionization is the removal of an electron from an atom by a very high energy photon
Electron is “kicked” off the atom by a photon with E > 13.6 eV(in this case- for hydrogen atom)
The resulting atom is called an ion and it has totally new electron orbits/energies.Thus, the spectral lines are completely different.
E = Energy
BB just right.BB too hot. hydrogen ionized.
BB too cool.
BB = blackbody (spectrum).
ionized atoms (ions)
excited atoms
ground-state atoms
Different atoms have different temperature dependencies because energy needed to ionize them is different.
Finally, to get temperature… use many ions. At any given temperature, some atoms are in ground state, some excited (creating absorption lines), and some ionized (creating absorption different lines from same element).
Spectral Class or TypeHistorically by Key Absorption Features
Now Understood as a Temperature Sequence
O, B, A, F, G, K, Mcoolerhotter
The Doppler Shift (light).
BLUE SHIFTHigher frequencyHigher energyShorter wavelength
RED SHIFTLower frequency
Lower energyLonger wavelength
The Doppler Shift (sound).
Higher pitch Lower pitch
REDSHIF
BLUESHIF
MID TERM EXAM 1
WEDNESDAY FEBRUARY 6 HERE @ USUAL TIME
All LECTURED MATERIAL AND READING ASSIGNMENTSBUT NOT
GRAVTITY AND KEPLERS LAWS