Review of. Oxygen (lavender light) Ceiling light (white) Flood light (white) Continuous/like a...
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Transcript of Review of. Oxygen (lavender light) Ceiling light (white) Flood light (white) Continuous/like a...
Review of
Oxygen (lavender light)
Ceiling light (white)
Flood light (white)
Continuous/like a rainbow
Thick bands of colors/ black spaces in between
Thin lines of color. Lots of black spaces in between.
NoNo
Nope
Depends
Spectral Lines from various elements
Compare & Contrast
Req. Energy; gives off
light
Glowing, white-hot metal (tungsten)
Mercury vapor causes phosphor coating to glow
Glowing gas (O2) or other gases
Continuous color (like rainbow)
Thick bands of color; black space in between
Very thin lines of color; lots of black space in between
Gas(es)Black spaces in between
Incandescent Fluorescent Bulb
Element Tube
(oxygen gas)
Incandescent uses a metal filament (tungsten) that glows white hot. The other two use energized gases to emit light.
Incandescent bulb’s spectrum is continuous (no black spaces). The other two have bands (thin lines) of color w/ black spaces in between.
The fluorescent bulb’s spectrum shows 5 thick bands of color, whereas the element (oxygen gas) tube has very thin lines of color.
Red light = lower frequency = less energy
Purple = higher frequency = higher energy
The Energy Levels (“orbits”) where electrons CAN “jump” out to (and then fall back from).
The specific Energy Levels/orbits where the electrons CAN’T go.
That electrons of atoms have specific Energy Levels. Electrons can jump from a lower to a higher energy level (orbit) but immediately fall back again & release this energy as light energy (as photons).
Frequency!
ET #33: What Big Ideas did Niels Bohr discover about the atom?
Bohr looked at the light spectrum given off by different elements.
•Determined electrons exist in different orbits (energy levels) around the nucleus.
•When electrons absorb energy, they get “excited” and jump to a higher energy level (orbit).
•When they “fall back”, electrons emit light energy: violet = higher energy emitted; red = lower energy.
http://www.colorado.edu/physics/2000/quantumzone/bohr.html
Electrons Jump!!
Smaller “jump” = Lower energy
Bigger “jump” = higher energy
Electron Energy Levels
nucelus
1st energy level
2nd energy level
3rd energy level
1999, Addison, Wesley, Longman, Inc.
Energyabsorbed
EnergyReleased
Spectra EmissionSpectra Emission16
When electrons are excited, they jump to higher energy levels.
As electrons fall back down, energy is re-emitted
the wavelength (color) depends on the energy level/orbit/shell from which it falls from
Electron Ladders
e-e- Ground state
Excited state
Electrons can only be atspecific energy levels,NOT between levels.