1. Development of Quantum Mechanics Planck and Einstein
AP Chemistry by
Diane Paskowski

2. Electromagnetic Radiation
One of the ways that energy travels through space
Three characteristics:
Wavelength
Frequency
Speed 
7.1

3. Characteristics
Wavelength (λ) – distance between two peaks or troughs in a wave 
Frequency (ν) – number of waves (cycles) per second that pass a given point in space
Speed – speed of light (2.9979×108 m/s)
c = λν
7.1

4. Classification of Electromagnetic Radiation
7.1

5. The Nature of Waves

6. Max Planck’s Nobel Prize
Energy can be gained or lost only in integer multiples of hν. 
A system can transfer energy only in whole quanta.
Energy seems to have particulate properties.
7.2

7. The Photoelectric Effect
7.2

8. Einstein’s Nobel Prize
Dual nature of light:
Electromagnetic radiation (and all matter) exhibits wave properties and particulate properties
Electromagnetic radiation is a stream of “particles” called photons.
Ephoton = hν = hc/λ

9. Photons Photons exhibit both particle and wave behavior
Dual nature of light
Photons DO have mass, in a relativistic way
No rest mass (never at rest)
E= mc m = E/c2