1. BIG topics... Light (electromagnetic radiation)
particle/wave dual nature of light
c, λ, ט & E
Quantum theory (wave mechanical model)
Bohr model of Hydrogen atom
absorption/emission
orbital shapes
Electron configurations
orbital, e- configuration
noble gas notation
Aufbau, Pauli & Hund (names not tested!)

2. Waves
Wavelength () - length of one complete wave. Common units: m or nm
Frequency () - # of waves that pass a point during a certain time period
Common Units: hertz (Hz) = 1/s = s-1
Amplitude (A) - distance from the origin to the trough or crest
Courtesy Christy Johannesson

3. Wavelength and Frequency
“nu” “lamda”
c = speed of light (3.0 x 108 m/s)‏
= frequency (s-1)‏
= wavelength (m)‏
c = 
Highest energy
Moderate energy
Lowest energy
E = energy (Joules or J)‏
h= Planck’s constant (6.626 x10-34 J s)‏
= frequency (s-1)‏
E = h 

4. Visible part of EM SPectrum
400 nm – 700 nm
Waves 1/33,000” long
Waves 1/70,000” long
Red
Orange
Yellow
Green
Blue
Indigo
Violet
PRISM
Slit
Ray of
White Light
All light is bent passing through a prism; violet is bent most and red least. A beam of sunlight produces a continuous band of rainbow colors showing that light is a mixture of colors.

5. Electromagnetic Spectrum
“The Electromagnetic Spectrum”
Description: This slide depicts the electromagnetic spectrum from gamma rays through radio waves.
Basic Concepts
         All forms of electromagnetic radiation are not identical
         All forms of electromagnetic radiation travel at the same speed in a vacuum (the speed of light, c = 3.00 x 108 m/sec).
         Wavelength and frequency are inversely proportional for a wave traveling at a constant speed.
         Energy and frequency are directly proportional for electromagnetic waves traveling at the speed of light.
Teaching Suggestions
Use this transparency to review the relationship of visible light to other types of radiation. Explain that all of the rays and waves shown are types of electromagnetic radiation. Point out that they differ essentially from each other only in energy level, wavelength, and frequency. Try the analogy of an ocean wave to help students understand electromagnetic waves. Question 6 can be used to assess the students understanding of wave velocity, wavelength, and frequency.
Questions:
List the ways in which visible light is different from the other types of radiation shown in the diagram.
List the ways in which all of the types of radiation shown in the diagram are similar.
You are told that sound waves cannot travel in a vacuum. Are sound waves a types of electromagnetic radiation? Explain your logic.
Radio waves can go around an obstruction if the obstruction is smaller than the radio wave’s wavelength. What would you expect to happen if visible light were beamed at a thin wire 2 x 10-5 centimeter thick? Explain your answer.
For electromagnetic waves traveling at the speed of light, the wavelength is inversely proportional to frequency, as expressed by the equation c = fl, where c = speed of light in vacuum (3.00 x 108 meters/second), f = frequency, and l= wavelength. Using this equation, calculate the frequency of a 3-meter radio wave traveling at the speed of light. Compare your answer with the diagram.
Suppose that at a particular beach the ocean waves are traveling at a speed of 2 meters/second. If you know that the distance between waves is 10 meters, can you calculate how often they hit the shore? Explain your answer.
For electromagnetic waves traveling at the speed of light, the energy of a single photon is expressed by the equation E = hf, where E = energy, f = frequency, and h = Planck’s constant, 6.6 x joules/hertz.
Which has more energy, a photon of visible light or a photon of radar, if both traveling at the speed of light?
Do you think you can calculate the energy of an ocean wave using this energy equation? Explain your answer.
Electromagnetic Spectrum

7. Excitation of Hydrogen Atoms

8. Return to Ground State

9. An Excited Lithium Atom
Excited Li atom
Energy
Photon of
red light
emitted
Li atom in
lower energy state

10. Quantum Theory Max Planck (1900)‏
Observed - emission of light from hot objects
Concluded - energy is emitted in small, specific amounts (quanta)‏
Quantum - minimum amount of energy gained or lost by an atom
Courtesy Christy Johannesson

11. Continuous vs. Quantized EnergyB
quantized
Energy A
continuous
A B
continuous quantized

12. Further away from nucleus means higher energy level…
Bohr Model of Hydrogen
Great theory, BUT it turned out to be totally wrong!! Next week we’ll see a better theory  e
Nucleus
Possible electron orbits

13. Emission Spectrum of Hydrogen
1 nm = 1 x 10-9 m = “a billionth of a meter”
410 nm
434 nm
486 nm
656 nm

14. Continuous and Line Spectra
Visible
spectrum
l (nm)
light nm Na H Ca Hg

15. Preview....Orbital Shapes