1. Electron Configurations
Radiant Energy
Quantum Theory

2. Electromagnetic Spectrum -or- Electromagnetic Radiation
Radiant energy
Waves (includes many kinds)
All move at the speed of light, x 108 m/s = c

3. Parts of a wave
Crest
Wavelength
Amplitude
Origin
Trough

4. Parts of Wave Origin - the base line of the energy.
Crest - high point on a wave
Trough - low point on a wave
Amplitude - distance from origin to crest
Wavelength - distance from crest to crest
Wavelength is abbreviated by the Greek letter lambda = l

5. Frequency The number of waves that pass a given point per second.
Units: cycles/sec or hertz (hz or sec-1)
Frequency = f

6. Electromagnetic Spectrum
Low energy
High energy
Radiowaves
Microwaves
Infrared .
Ultra-violet
X-Rays
GammaRays
Low Frequency
High Frequency
Long Wavelength
Short Wavelength
Visible Light

7. Frequency and Wavelength are inversely related
As one goes up the other goes down.
c = lf
Different frequencies = different colors of light.
The whole range is called a spectrum.

8. Example 1
What is the wavelength of blue light with a frequency of 8.3 x 1015 hz?
c = 3.00 x 108 m/s
f = 8.3 x 1015 hz
l = ?
c = l f
3.00 x 108 m/s = l 8.3 x 1015 hz
l = x 108 m/s = 3.6 x 10-8 m
8.3 x 1015 hz

9. Example 2
What is the frequency of red light with a wavelength of 4.2 x 10-5 m?
c = 3.00 x 108 m/s
f = ?
l = 4.2 x 10-5 m
c = l f
3.00 x 108 m/s = 4.2 x 10-5 m f
f = x 108 m/s = 7.1 x 1012 Hz
4.2 x 10-5 m

10. Light is the link to electrons
The study of light led to the development of the quantum mechanical model.
Planck proposed energy can only be absorbed or released from atoms in fixed amounts called quanta.
The relationship is E = h f
E is the energy
f is the frequency
h is Planck’s constant = x J x sec.
E and f are directly related.

11. Photoelectric effect
Electrons are ejected from the surface of a metal when light shines on the metal.
Valid only at certain frequency.
Einstein explained this phenomenon using Planck’s theory.
Light contains quanta of energy that behave like particles or photons.
Light is a Particle and a Wave?

12. Quantized Energy and Photons
The Photoelectric Effect