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Three Types of Spectra. Hydrogen. Hydrogen and Helium. Hydrogen. Helium. Nitrogen and Krypton. Nitrogen. Krypton. Argon and Mercury. Argon. Mercury. Neon. What do you notice about the spectrum for each of the elements?. They are unique to each element. .
E N D
Hydrogen and Helium Hydrogen Helium
Nitrogen and Krypton Nitrogen Krypton
Argon and Mercury Argon Mercury
What do you notice about the spectrum for each of the elements?
They are unique to each element. Each element’s spectrum is a “fingerprint” for that element. It can be used to identify the element.
Test Your Spectral Skills…. • Look at the different spectra below. • Look at the unknown spectrum. • Which two elements make up the unknown spectrum?
By the way….. How does a bright line, or emission spectrum, form?
Spectrum Excited State n=4 UV Excited State n=3 Excited State unstable and drops back down Vi s ible Excited State But only as far as n = 2 this time n=2 • Energy released as a photon • Frequency proportional to energy drop IR n=1 Ground State
http://www.visionlearning.com/library/flash_viewer.php?oid=1347&mid=51http://www.visionlearning.com/library/flash_viewer.php?oid=1347&mid=51
Summary • Electron normally in Ground State • Energy supplied [ as heat or electricity] • Electron jumps to higher energy level • Now in Excited State • Unstable • Drops back to a lower level
Energy that was absorbed to make the jump up is now released as a photon • Frequency depends on difference in energy levels [ E2 - E1 = hf ] h is Plank’s Constant and f is frequency of light • When electron falls to n = 1 level gives UV Range n = 2 level gives Visible Range n = 3,4 or 5 levels gives IR Range