1. Atomic/Quantum Theory

2. The Structure of an Atom
Atoms have nuclei of protons (+) and neutrons (0)
The number of protons (+) are most important, they identify the atom
Neutrons (0) just stabilize the protons, their number can vary

3. Electrons Electrons (-) are also essential to atoms
Usually equal number of protons (+) and electrons (-) to cancel each other’s charge
Electrons exist in ‘shells’ around a nucleus

4. Electrons
Electrons (-) always want to be at the lowest stable energy level possible
Can not exist between states, only at specific states
These states are of a specific quantity, e.g. quantum mechanics

5. Electron Orbits are Clouds

6. Atoms Create Light

7. Energy Levels
What happens when electrons jump between quantized energy levels?
Electrons can be pushed to higher levels using heat or electricity.
Once at a higher level they want to fall back down.

8. Energy Levels Once at a higher level they want to fall back down.
When they do a quantized photon is released.
Bigger jump = higher energy = higher f

9. Energy Levels
We can see these quantum jumps in atomic emission spectra

10. The Photoelectric Effect
We understand that photons are emitted at quantized wavelengths.
How do we know they are particles?
When electrons of high enough energy strike metal they can eject electrons from the metal

11. The Photoelectric Effect
When photons of high enough energy strike metal they can eject electrons from the metal
High energy = high frequency = low wavelength
Low energy photons can not do this, no matter how bright the light
Brighter light = more electrons, NOT higher energy

12. Photons are Particles
Photoelectric interactions help demonstrate that photons are also a particle
A beam of electrons also behaves similarly to a beam of photons
Can be diffracted/reflected/etc…

13. The Electromagnetic Spectrum

14. The EM Spectrum

15. Radio λ≈1000m Building sized Low Energy, safe Radio, television, etc…
Can pass right though most things

16. Microwave λ≈0.1m Resonates with water molecules
Used for radar and cooking Hot Pockets
Blocked by grating on microwave ovens
Dissipated by anti-radar coatings

17. Infrared λ≈0.0001m Needlepoint sized Heat rays Feel rather than see
Blocked by most physical objects

18. Visible λ≈0.0000005m Size of bacteria Full RGB spectrum
16,777,216 RGB colors -->
Everything we see is just reflected light in this region

19. Ultraviolet λ≈0.0000001m Size of organic molecules
Almost dangerous energy
Can cause cancer
Partially blocked by air
Can cause fluorescence

20. X-ray λ≈0.000000001m Size of atoms Dangerous in large doses
Used in lots of scientific instrumetns
Blocked by bones, lead vests

21. Gamma Ray λ≈0.00000000001m Size of atomic nuclei
VERY high energy, dangerous
Can travel massive distances
No super powers, just melted DNA

22. The EM Spectrum

23. Review Quantum Theory The Structure of an Atom Electrons Energy Levels
The Photoelectric Effect
Photons are Particles
The EM Spectrum