What’s wrong with this picture? Take out: -Your lab notebook open to your warm up section -Examining Emission Spectra & Getting Charged W.S. -Grab your homework sheet! (Back Table)
Warm-up How are atoms “excited” in the element tubes? What does it mean the atoms are “excited”? In an emission spectra what color has the lowest energy? RED
An Excited Electron Emission Energy Photon of light emitted Ground energy state Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 326
Review Homework- 6 minutes With a partner: Discuss what the biggest difference between how the incandescent bulb works compared to the element tube? Compare each others drawings for #3. Were they the same? Different? Why did you chose to draw it like that? Left side partner: Explain #4 to right partner Right partner: Explain #5 to left partner Where are you (individually) on the LT? Record this on your HW sheet, then turn in
Why More Lines than Electrons? He Ne
Every atom is quantized! Excited states! Quantized – only certain values for energy levels are allowed Every atom is quantized! Ground State
An Excited Electron Emission Energy Photon of light emitted Ground energy state Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 326
Electron Ladders: Absorption Electrons can only be at specific energy levels, NOT between levels. The farther an electron falls, the higher energy photon it gives off Ex: red= little fall Ex: ultra violet= big fall! Excited state Ground state e- e-
Niels Bohr's Experiment Bohr examined the emission spectra of Hydrogen and created a model of the atom based on his data Thought electrons had restricted, circular orbits around the nucleus Fit his hydrogen data perfectly! Did not fit other atoms
Why is this important? Electrons in hydrogen atoms can only have specific energy levels since they can only give off certain colors We can use the colors to hypothesize how electrons orbit each atom! Ex: can use info to find out what stars are made of
Bohr and the Quantum Theory When electrons fall they release Light Energy Explains: Empty spaces Why electrons didn’t get “sucked” into the nucleus Clip: Bohr’s Model of the Atom
Safety! Tie hair back! Goggles! Common sense! Awareness! Help your buddy!
Flame Emission Spectra Photographs of flame tests of burning wooden splints soaked in different salts. methane gas wooden splint sodium ion calcium ion copper ion strontium ion Include link to web page http://www.unit5.org/christjs/flame%20tests.htm
Fireworks
Homework: Finish Flame Lab Exit Task What part of the atom is giving off the light, and how it is happening? (draw it using a bohr model!!) Homework: Finish Flame Lab