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

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

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

Classification of Electromagnetic Radiation 7.1

The Nature of Waves

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

The Photoelectric Effect 7.2

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

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= mc2 . . . m = E/c2