126 Lght and Atomic Spectra126的光与原子光谱

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1、12.6 Light and Atomic SpectranThe quantum mechanical model of the atom grew out of the study of light.12.6 Light and Atomic SpectranIn the wave model, light is considered to consist of electromagnetic waves that travel at a speed of 3.0 x 108 m/s (186,000 mi/s). includes radio waves, microwaves, vis

2、ible light, infrared and ultraviolet light, X-rays, and gamma rays.12.6 Light and Atomic Spectra the height of the wave from the origin to the crest.(, lamda) the distance between the crests(, nu) the number of wave cycles to pass a given point per unit of time12.6 Light and Atomic SpectranThe speed

3、 of light (c) in a vacuum is constant and is equal to frequency () multiplied by wavelength (). Equation: c = nThis equation can be rewritten as follows: = or = Note: speed of light = c (must be in )frequency = (must be in reciprocal seconds () or hertz, )wavelength = (must be in )12.6 Light and Ato

4、mic SpectranWavelength and frequency have an inverse relationship.12.6 Light and Atomic SpectranLight refers to a small part of the electromagnetic spectrum that our eyes can see12.6 Light and Atomic SpectranEach color in the spectrum (ROYGBIV) blends into the next.12.6 Light and Atomic SpectranElem

5、ents emit light when energy is passed through them.nElectrons absorb energy and are excited to higher energy levels; they then release the energy in the form of light when they return to their ground state.12.6 ExamplenCalculate the wavelength of the yellow light emitted by a sodium lamp if the freq

6、uency of the radiation is 5.10 x 10-14s-1.nKnown: c = 3.0 x 108 m/s = 5.10 x 10-14nSolution - Use the equation: = = = = 5.88 x 10-7 m12.6 Concept Practice11. List the colors of the visible spectrum in order of increasing wavelength.12. What is meant by the term frequency of a wave? What are the unit

7、s of frequency? Describe the relationship between frequency and wavelength.12.6 Practice13. What is the frequency of radiation whose wavelength is 5.00 x 10-6cm? In what region of the electromagnetic spectrum is this radiation?12.6 Practice14. A hydrogen lamp emits several lines in the visible region of the spectrum. One of these lines has a wavelength of 6.56 x10-5 cm. What are the color and frequency of this radiation?