apch04sc - 4 Electronic Structure & the Per. Table Wave...

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Wave Ideas You Should Know (1 of 16) EMR e lectro m agnetic r adiation … wavelength ( λ ) the distance from crest to crest or trough to trough. amplitude the distance from the equilibrium point to the crest or trough. frequency ( ν ) the number of waves that pass a point per second. (Hz, s –1 , 1 / s ) continuous spectrum a “normal” rainbow that contains all of the colors (ROYGBV). line spectrum a spectrum that only contains certain bright lines that result from electron transitions within an atom. Wave Calculations (2 of 16) λ · ν = c c = 3.00 x 10 8 m/s [speed of light] E = h ν h = 6.626 x 10 –34 J·s [Planck’s constant] E = h c λ Energy of Level “n” in the Hydrogen atom: E n = – A n 2 A = 2.18 x 10 –18 J [Arrhenius constant?] NOTE: You can learn the Balmer equation or the Rydberg equation listed on pp. 108 & 109. I suggest you use the above equations to calculate the wavelengths or frequencies of light emitted when electrons change energy levels. The Balmer Series (3 of 16) When the electron “drops” to energy level n=2, visible light is emitted. The bight line spectrum observed is called the Balmer Series of lines. [Memorize this info. ..] 3 2 red 4 2 blue-green 5 2 blue-violet 6 2 violet All the lines result from an electron transition to level n=1 are too high energy to be visible… UV [Lyman Series] All the lines that result from an electron transition to levels n=3 [Paschen], n=4 [Brackett] and n=5 [Pfund] are too LOW energy to be visible. The De Broglie Wavelength of Electrons (4 of 16) Two equations can be combined into one to allow you to calculate the wavelength of a particle : E = mc 2 E = h c λ mc 2 = h c λ mc = h λ or more generally, mv = h λ λ = h mv h = Planck’s constant, m = mass of particle (in kg), v = velocity of particle (in m/s).
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Standing Waves (5 of 16) Standing waves are something that waves do…
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apch04sc - 4 Electronic Structure & the Per. Table Wave...

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