Particle Nature of Lightpage 49 of Notebook

VISIBLE LIGHT ELECTRONS

Objective:

• To understand the duality of Particles/Waves

• To understand how light interacts with matter

What is The Particle Light Theory?

• In the particle light theory, waves exist as particles with wave like properties.

• The properties they have are frequencies, energy, and wavelengths.

The Wave model of light cannot explain:

1. Why heated objects only emit certain frequencies.

2. Why some metals emit electrons when light of a specific frequency shines on them.

What is the Quantum Concept?

• Matter can gain or lose energy only in small specific amounts called quanta.

• Explained why heated objects emitted certain frequencies/energy

What is a quantum?

• The minimum amount of energy that can be gained or lost by an atom.

What is Planck’s Constant?

• 6.626 x 10 -34 j . S

• Used to calculate the amount of energy in a quantum

What is the photoelectric effect?

• Electrons called photoelectrons are emitted from a metals surface when light of a certain frequency shines on it (Albert Einstein-1905)

What is a photon?

• A particle that has no mass and carries a quantum of energy

Calculations: Energy of a Photon

E-energyh-planck’s constantV-frequency

Ephoton = hv

Problem Solving

• Page 143 - Example Problem

• Class work – Page 143 Problem 5

• Homework – Page 143 Problem 6 & 7

Bohr’s Model of the Atom

Page 50 of Notebook

Quantum Model of the Atom

Page 50 of Notebook