Last saved by: Susan Keating

I. Waves & Particles

Electrons in Atoms
Waves
•	Wavelength (λ) - length of one complete wave
•	Frequency (ν) - # of waves that pass a point during a certain time period
•	hertz (Hz) = 1/s
•	Amplitude (A) - distance from the origin to the trough or crest
Waves
Electromagnetic Spectrum
EM Spectrum
EM Spectrum
•	Frequency & wavelength are inversely proportional

•	Quantum Theory
•	Planck (1900)
•	Observed - emission of light from hot objects
•	Concluded - energy is emitted in small, specific amounts (quanta)
•	Quantum - minimum amount of energy change

•	Einstein (1905)
•	Observed - photoelectric effect
•	Concluded - light has properties of both waves and particles “wave-particle duality”
•	Photon - particle of light that carries a quantum of energy