ground state vs. excited state ground state – all electrons are in the lowest possible energy...
TRANSCRIPT
Ground State vs. Excited State
Ground State – all electrons are in the lowest possible energy levels (normal) ex. 2 – 8 – 18 – 32
Excited State – if given additional energy, electrons will “jump up” to higher energy levels, temporarily.
Excited State ex. 2 – 5 – 2 Ground State ex. 2 – 7
Spectra
(bright line)
(dark line)
Bright Line = Emission SpectraHow does this happen?
“Excited electrons” at higher energy levels will eventually release the extra energy and “fall back down” to ground state conditions.
During the “fall back”, energy is released as Visible Light Energy.
Wavelengths = Energy = Color Bands
Bright Line Spectra
Energy levels are NOT evenly
separated.
Bright Line – Emission Spectra
How are spectra formed?
Niels Bohr1913
Danish chemist
Bohr model of atom:
http://www.chemeng.uiuc.edu/~alkgrp/mo/gk12/quantum/
Bright Line Spectra
Each element has a specific electron configuration and a corresponding emission spectrum.
Emission (bright line) spectrum can be used to identify (“fingerprint”) each element.
http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/physics/PhysicsInitiative/Physics2000/applets/a2.html
So Dude, check out the
colors!
Do the spectra lab.
Bright Line – Emission Spectra
Spectra
(bright line)
(dark line)
Flame Tests
- burn metal salts in a flame and observe/record the color
- compare colors to known standards for metals
- spectrascope not required
Sodium (Na) – Yellow flame
with Na salts like NaCl, NaBr
Potassium (K) –Violet flame
with KCl, KBr, etc.