1. Atomic Spectra and Flame Test

2. The Lab
What observations did you make observing White Light?

4. The Lab
What observations did you make looking at the spectrum tubes of Hydrogen, Helium, and Neon?
What observations did you make looking at the Fluorescent Lights?

5. Hydrogen
Hydrogen
Helium
Neon

6. Why??!!
This property of different elements puzzled scientist for years
Einstein, Bohr, Heisenberg, Plank, Schrodinger
To understand what is going on…
Light
The Atom

7. Light and the Electromagnetic Spectrum

8. Light and the Electromagnetic Spectrum
Light Behaves Like a WAVE!!
Has a WAVELENGTH
Relationship between Wavelength and Energy!!
LONG Wavelength is LOW energy
SHORT Wavelength is HIGH energy
Long Wavelength
Short Wavelength

10. Light and the Electromagnetic Spectrum
Light Behaves like a PARTICLE!!
Proposed by Einstein
Said that Light was tiny “packets” of energy
Those packets he called PHOTONS
Einstein said that photons are QUANTIZED
Each photon has a Specific amount of energy
Used this to explain the Line Spectra of atoms

11. The Atom What is the structure of an Atom?
Made of Protons, Neutrons, and Electrons
Nucleus – Protons and Neutrons
Electron Orbitals or Clouds – Electrons

12. The Atom A few problems with the atom: Bohr’s Model
All those protons in the nucleus
The electrons and the protons
All those electrons round the nucleus
Bohr’s Model
Nucleus has protons and neutrons
Electrons in ORBITS
Imagine a “solar system “

13. The Atom Einstein and Bohr’s Model
Photon strikes and atom in its GROUND STATE
Photon is a quantized amount of energy - Atom absorbs that energy
Atom enters and EXCITED STATE
Then the atom emits that extra energy
Atom returns to the GROUND STATE
But HOW does that explain the Line Spectra!!??

14. The Atom
First thing is to figure out what ACTUALLY absorbed that extra energy form that photon…
What are our choices?
Proton
Neutron
Electron
What is the most likely choice!?

15. The atom THE ELECTRONS!!! I need a Volunteer!
Let’s take a look at a LIVE DEMO!!
I need a Volunteer!

17. The Atom Modern Model of the Atom:
Electrons are in ORBITALS, Electron Clouds
Not in ORBITS like planets
Each ORBITAL has an associated energy
Electrons can be EXCITED from a LOW ENERGY ORBITAL to a HIGHER ENERGY ORBITAL by absorbing a Photon
When moving from a HIGH ENERGY ORBITAL to a LOWER ENERGY ORBITAL, the electron emits a PHOTON from the electromagnetic spectrum

18. The Atom

22. Flame Test and Spectrum Tubes
Hydrogen’s Tube was Pink/Purpleish
Hydrogen has blue and red spectral line
Color blend

23. Flame Test and Spectrum Tubes
Each element has a different set of spectral lines
They blend to produce the colors we see in a flame test!

25. Why are spectral Lines useful?
Pluto
Nitrogen

26. Questions!?