Flame Test Recap WCHS Chemistry LOW ENERGY: red
HIGH ENERGY: violet They JUMP to higher energy levels/orbits.
Ground State = e- are in the LOWEST energy orbits (closest to nucleus) Excited State = e- jump to HIGHEST energy orbits (furthest from nucleus) PHOTON
When e- fall back down from excited state to ground state. Electrons need energy in order to jump up to the excited state. They will never fall down and release a photon if they dont jump up first!
Notes #4: History of the Atom (part 4) - Quantum Mechanics WCHS Chemistry
BOHR MODEL OF THE ATOM By mid-1920, we discovered Bohr wasnt exactly correct Model needed to be modified, but no one could
do it! THE BIG QUESTION WAS... Is an electron a particle or a wave?
Yes! :) Its BOTH! This realization led scientists to a new model: WHAT WE
Quantum Mechanics NOW KNOW! LOUIS-VICTOR DE BROGLIE (1924) Electrons show wave-like properties. POSITIVE NUCLEUS
NEGATIVE ENERGY CLOUD ERWIN SCHRDINGER (1926) Developed a COMPLEX math
equation to describe electron motion. Notes from Schrodingers lecture at Georgia tech:
CONCLUSION We have NO IDEA where an electron really is! NO ORBITS!!!
WERNER HEISENBERG (1925) Heisenberg Uncertainty Principle It is impossible to know both the position and the momentum of an electron at the same time! SPEED &
DIRECTION WHERE Think of a picture of a car....
Can you tell the exact position of the car? Which direction its going?
How fast its going? If its moving at all?
Now think of this picture of a car... Can you tell the exact position of the car? Which direction
its going? How fast its going? If its moving at all?
WERNER HEISENBERG (1925) Heisenberg Uncertainty Principle It is impossible to know both the position and the
momentum of an electron at the same time! SPEED & DIRECTION We have to use probability
to tell us where an electron is most likely located! WHERE
ORBITALS Example: If you were a betting person, where would you look for a bee? = regions of space where there is a high
probability of finding an electron. Each orbital can hold 0, 1, or 2 electrons No more than 2!! Orbitals have different sizes, shapes, & names!