CHEM 121 Chapter Notes - Chapter 2: Threshold Energy, Emission Spectrum, Wave Equation
Document Summary
2. 1: the nature of radiant energy and electromagnetic spectrum. Electromagnetic spectrum (visible light, infrared radiation, microwaves, radio waves, x rays, and so on) Frequency (v, greek nu) (# of wave peaks that pass by given point per unit time) Hertz (hz; 1 hz = 1 s. Wavelength (greek lambda) (distance from one wave peak to the next) Amplitude (height of wave, measured from center line between peak and trough) Lambda = c/v or v = c/ lambda. 2. 2: interaction of radiant energy with atoms: balmer"s equation. Red = long-wavelength end of spectrum (780 nm) Violet = short-wavelength end of spectrum (380 nm) Line spectrum (series of discrete lines on an otherwise dark background) 2. 3: particle-like properties of radiant energy: photoelectric effect and planck"s postulate. Work function (amount of energy necessary to eject an element) Low-energy photons bounce off metal surface, but single photon at or above certain threshold energy can break the metal and dislodge an electron.
