Download Wave Particle Duality Power Point NOTES

Wave-Particle Duality
Electronic structure (electron configurations)
- base for many chemistry concepts.
ex: molecular geometry & chemical reactivity.
Electromagnetic radiation
is the probe used to obtain knowledge of
the electronic structure.
Electromagnetic Radiation
Short Wavelength =High Frequency = High ENERGY
Long Wavelength = Low Frequency = Low ENERGY
Electromagnetic radiation propagates through space as
a wave moving at the speed of light.
WAVE MODEL
c = 
C = speed of light (3.00 x 108 m/s)
 = wavelength, (m); distance between 2 peaks
 = frequency, (hertz = hz, sec-1); # peaks per time
INVERSE
Is this a direct or inverse relationship? ___________
Direct = DDSS
Direct, Divide, Same variable direction, Straight line
What is the speed at which radio waves travel?
3 x 108 m/s
Which one travels faster red or blue light? Same Speed = 3 x 108 m/s
Which has more energy red or blue light? BLUE = higher frequency
Constructive Interference
Waves - SYNCHRONIZED -ENLARGED wave result bright bands
Destructive Interference
Waves -NOT SYNCHRONIZED - waves cancel out result black/gray bands
De Broglie’s Equation
• Broglie’s stated that an object in motion
behaves as both particles & waves, just as light
does.
• Electrons are WAVES in FIXED LOCATIONS
which means they are QUANTIZED (quantity)
wavelengths.
Sizes of s orbitals
Orbitals of the same shape grow larger as n increases…
Nodes are regions of low probability within an orbital.
Heisenberg Uncertainty Principle
“One cannot simultaneously determine
both the position and momentum of an
electron.
Schrodinger (CAT) Wave Equation
d
h

8  m dx
2
2
2
2
V


E
Equation for probability of a single electron
being found along a single axis (x-axis)
Schrodinger wave equation & Heisenberg Uncertainty principle
provided the framework for the QUANTUM THEORY!
Realized hot object do NOT emit
electromagnetic energy
continuously but as energy in
small specific amounts called
quanta (wave)
Particle Model (Planck’s Equation)
Ephoton= h
E
photon=
Energy (Joules = kg·m2/s2)
h = Planck’s constant (6.626 x 10-34 J·s)
 = frequency (hertz = hz, sec-1)
Energy is directly related to FREQUENCY.
What is photon? – particle of light
ABSORPTION
Ground State
Excited State
EMISSION
Camp Fire
Hot Metal
Spectroscopic analysis : wavelength analysis
Continuous Emission Spectrum: produces all colors
Bright Line emission spectrum: produce specific wavelengths
** Wavelength analysis is a FINGERPRINT for element.
SUMMARY
Wave Theory
Formula: c = 
Measurable characteristics - Frequency & wavelength
Light can interfere and diffract (bend)
Particle Theory
Formula E = h
Light when it absorbs/emits by matter
1) photoelectric effect (shiny metal)
2) Absorption of Light by HOT objects
3) Line-Emission Spectra of elements
Light has mass!!
Light is a particle!!
It both a wave-particle called
PHOTON (zero mass carrying a
quantum of energy)
Einstein’s Equation
E = mc2
CoMbInInG FoRmUlA’s
Wave Equation:
c =  
 = c/
 = c/ inserted into
Planck’s (Particle) Equation E = h
E = (hc)/
Einstein’s Equation E = mc2
Combine (hc)/ = mc2
(hc) = mc2 
 = (hc) / (mc2)
 = h/mc
or
…”c” cancels out…..
m = h/ c
note: c = speed = velocity
What does this MEAN?
Anything that has both MASS and VELOCITY (movement) has a
corresponding WAVELENGTH!
Observed Spectra of Elements
Wave-Particle Duality
JJ Thomson won the Nobel prize for describing the
electron as a particle.
The
electron is
a particle!
The
electron is
an energy
wave!
George Thomson won the Nobel prize for describing
the wave-like nature of the electron.