1. Evolution of Atomic Structure

2. Dalton 1805 Billiard Ball Model
Composed of indestructible, indivisible atoms
Identical for each element but different from other elements

3. Thompson 1904 Raisin Bun Model
Atoms have electrons embedded in a positive material

4. Rutherford Nuclear Model
Atom is composed of a tiny nucleus and orbiting electrons
Most of the atom is empty space
Very small electrons occupy most of the space
Nucleus is composed of protons and neutrons
Key experiment:
Gold Foil Experiment

8. Quantum Theory
Hot Body Spectrum

9. Continuous Spectra?
Mathematical model’s could not explain the entire distribution of light at the time
Max Planck surmised that the spectra was not continuous but rather had steps

10. Photoelectric Effect
When specific wavelengths of light hit some metals electrons will be displaced
The intensity of the light did not effect the current produced
The wavelength of light did effect the current

12. Bohr Model Quantized Model Electrons exist in exact orbits/shells
The distance from the nucleus of each orbit is quantized
Used Balmer’s line spectra

13. http://www. upscale. utoronto

14. Types of Spectra

15. Line Spectra

16. Bohr’s Postulates Bohr’s First Postulate
Electrons do not radiate energy as they orbit the nucleus. Each orbit corresponds to a state of constant energy (called a stationary state).
Bohr’s Second Postulate
Electrons can change their energy only by undergoing a transition from one stationary state to another.

17. Quantum Numbers

18. Principal Quantum Number
Main Shell

19. Secondary Quantum Number
The secondary quantum number relates primarily to the shape of the electron orbit. The number of values for l equals the volume of the principal quantum number.

20. Magnetic Quantum Number
The magnetic quantum number, ml, relates primarily to the direction of the electron orbit. The number of values for ml is the number of independent orientations of orbits that are possible.
Values of ml range from –l to +l

21. Spin Quantum Number
The spin quantum number, ms, relates to a property of an electron that can best be described as its spin. The spin quantum number can only be 1/2 or1/2 for any electron.

22. p. 162 – 184
p # 1-6, 11
p. 173 #1-5
p. 180 # 1-4, 7, 9, 10
p. 184 # 1-6