1. Flame Test Recap
WCHS Chemistry

2. They JUMP to higher energy levels/orbits.
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)

3. 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 don’t jump up first!

4. Notes #4: History of the Atom (part 4) - Quantum Mechanics
WCHS Chemistry

5. BOHR MODEL OF THE ATOM
By mid-1920, we discovered Bohr wasn’t exactly correct
Model needed to be modified, but no one could do it!

6. Is an electron a particle or a wave? Yes! :) → It’s BOTH!
THE BIG QUESTION WAS...
Is an electron a particle or a wave?
Yes! :) → It’s BOTH!
This realization led scientists to a new model:
Quantum Mechanics
WHAT WE NOW KNOW!

7. LOUIS-VICTOR DE BROGLIE (1924)
Electrons show wave-like properties.
POSITIVE NUCLEUS
NEGATIVE ENERGY CLOUD

8. ERWIN SCHRÖDINGER (1926)
Developed a COMPLEX math equation to describe electron motion.
Notes from Schrodinger’s lecture at Georgia tech:

19. CONCLUSION
We have NO IDEA where an electron really is!
NO ORBITS!!!

20. 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

21. Think of a picture of a car....
Can you tell the exact position of the car?
Which direction it’s going?
How fast it’s going?
If it’s moving at all?

22. Now think of this picture of a car...
Can you tell the exact position of the car?
Which direction it’s going?
How fast it’s going?
If it’s moving at all?

23. WERNER HEISENBERG (1925) Heisenberg Uncertainty Principle
It is impossible to know both the position and the momentum of an electron at the same time!
We have to use probability to tell us where an electron is most likely located!
SPEED & DIRECTION
WHERE

24. 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!