1. Chemistry Chapter 5
Ch5 Notes #1

2. Light and Quantized Energy
An element’s chemical behavior is connected to electron arrangement
Electron arrangement and chemical properties are connected to light energy
Form of energy that exhibits wave- like behavior….
Ex. Visible light, x-rays, microwaves, etc….
EM Spectrum – all electromagnetic radiation

3. Waves
Described by:
Wavelength: Shortest distance between 2 equivalent points on a continuous wave
Amplitude: height from origin to crest
Frequency: how many complete waves pass a point in a given amount of time
Hertz; waves per second
Speed of light (c)- wavelength x speed
3.00 x 108 m/s

4. Waves - review

5. Light – Wave or particle?
Max Planck
Quantum – minimum amount of energy that can be gained or lost by an atom…
Albert Einstein (1905)
Completion of the particle model
EM radiation = stream of tiny particles (bundles of energy) that move like a wave – called photons
Photon = a particle of EM radiation with no mass that carries a quantum of energy

6. Light – Wave or particle?
EM radiation – wave and particle like!!
Increasing Energy

7. Atomic Emission Spectra
Set of frequencies of the electromagnetic waves emitted by atoms of an element
Each element gives off a unique set of frequencies
Quantum Mechanics
Electrons emit certain energy (related to wavelength)
Each spectra consists of several “lines” of color…not a continuous range like a visible spectra (rainbow) – there are “black” spaces in between the colors.

8. Example

9. Real Life Uses Fireworks Neon Signs Bon-Fire (Old Christmas lights)
Rainbows
Scientists can learn what stars are made of by observing the spectrum they emit
Photoelectric panels (solar houses, calculators)