1. The Development of a New Atomic Model
Rutherford- did not explain how the atom’s negatively charged particles are distributed in the space surrounding it’s positively charged nucleus.

3. The New Atomic Model
Researcher used investigations into the absorption and emission of light
Studies revealed a relationship beteen light an atom’s electrons
New understanding about the nature of energy, matter, and atomic structure.

4. Properties of Light
Before 1900, light was thought to behave solely as a wave
Wavelike description
It is type of electromagnetic radiation
Forms part of the electromagnetic spectrum
Significant wavelike motion characterized by wavelength and frequency
Wavelength (λ) is the distance between corresponding points on adjacent waves.
Frequency (v) is the number of waves that pass a specific point in a given time, usually one minute.

5. Frequency and wavelength are mathematically related to each other
c=λv c is the speed of light, a constant
There for λ, wavelength in m, is inversely proportional to v, frequency in s-1.
As wavelength decreases frequency increases and vice versa

6. The Photoelectric Effect
The photoelectric effect refers to the emission of electron when light is shines on a metal.

7. The Photoelectric Effect
The mystery was…..
No electron would be emmited if the lights frequency (v) was below a certain minimum.
No matter how intense (W) the light was.
Wave theory state that light of any frequency could supply enough energy to eject an electron.

8. The Particle Description of Light
Max Planck (1900 German Physicist)
Studied emission of light by hot objects
He proposed the hot objects do not emit electromagnetic energy continuously (as would be expected if all we were dealing with was a wave)

9. The Particle Description of Light
Quantum- a measure of energy that is the minimum quantity of energy that can be lost or gain by an atom
Planck proposed a relationship between a quantum of energy and the frequency of radiation
E=hv
E= energy in joules, v is frequency (s-1),
h= a fundamental physical constant now know as Planck’s constant = 6.626x

10. The Duality of particles and waves
Albert Einstein expanded on Planck’s work and proposed a radical idea
Electromagnetic radiation has a dual wave-particle nature
While like light act like a wave
It is a stream of particles
Each particle carries a quantum of energy
These particles are called photons
These particles have zero mass but carry a quantum of energy

11. This explained the photoelectric effect
Einstein explained
Electromagnetic radiation is only absorbed by matter in whole numbers
In order for an electron to be rejected from the surface of the metal it must be struck by a single photon possessing at least a minimum energy required to knock the electron off.
Every metal has a different frequency

12. Home work Pages 124-125 #1-25 Complete sentences
If it is a multiple choice problem, select the letter choice them write a true complete sence out of the question and the choice: DO NOT COPY THE QUESTIONS
If it is a calculation, show equation used and ALL work
Have a great Thanksgiving!!!