Transcript Atomic Structure Teaching Resources

Atomic Structure Teaching
Resources
Eric Grunden
Raleigh Charter High School
Raleigh, NC
What’s Important?
• Chemistry EOC (not that this matters
anymore…)
•
•
2.01 Analyze the historical development of the current atomic theory.
– Early contributions: Democritus and Dalton.
– The discovery of the electron: Thomson and Millikan.
– The discovery of the nucleus, proton and neutron: Rutherford and Chadwick.
– The Bohr model.
– The quantum mechanical model.
2.02 Examine the nature of atomic structure.
– Subatomic particles: protons, neutrons, and electrons.
– Mass number.
– Atomic number.
– Isotopes.
What’s Important?
• AP Chemistry
1. Evidence for the atomic theory
2. Atomic masses; determination by chemical and physical means
3. Atomic number and mass number; isotopes
4. Electron energy levels: atomic spectra, quantum numbers, atomic orbitals
5. Periodic relationships including, for example, atomic radii, ionization energies,
electron affinities, oxidation states
My Model
The Atom
•Atomism
–Pre-socratics/Aristotle
•Dalton
–The “modern” atomic theory
•Thomson
–electron/plum pudding model
•Becquerel/Curie/radioactivity
•Rutherford
–Nucleus/Gold Foil experiment
•Millikan
–qe/”oil drop” experiment
•Nuclear transformations
–Rutherford again (transmutations)
–Decay modes
The Electron
•Light as a wave
•Kirchoff/Bunsen
–Emission spectra
•Balmer/Rydberg
•Planck
–Development of quantum concept
–Blackbody emitters
–“ultraviolet catastrophe”*
•Bohr Model
•Schrödinger Model
–Electron configurations
–orbital diagrams
The Atom
• Primary Documents
– Dalton reading
• Simulations
– Gold Foil Experiment (requires Java –
standalone/web)
• The APE MAN!
– Atomic Number = Protons = Electrons
– Mass Number = Atomic Number + Neutrons
Primary Documents!
• Be the envy of your Social Science
colleagues!
– Dalton’s A New System of Chemical Philosophy (suitable for moderate readers)
– Bohr’s On the Constitutions of Atoms and Molecules (very readable, though
complex; complete with math for the truly adventurous)
– Others available by search or from the Chemteam website.
•
•
•
Excerpting is the way to go
Pair students and have them explain passages to each other
Scalable up to more advanced students
The Electron
• Challenging Concepts!
– Revolutionary period – not “normal science”
– Highly abstract nature
– Cognitive dissonance is good!
• History of Light and electrons are
intertwined…
Faraday suggests
electricity and
magnetism related
Light theory
Newton proposes particle theory
of light
Huyghens’
Principle
supports
waves
Hooke
proposes
wave theory
Photoelectric Effect
(supports particle
interpretation –
Einstein relates to
Planck’s quanta
concept)
Maxwell’s Equations
relate light, electricity,
magnetism
Hertz detects radio
waves (supports
wave theory)
Young: 2-slit experiment
shows wave behavior
De Broglie proposes
matter has wavelike qualities
Planck puts
idea in
Einstein’s head
1600
1700
1800
1900
1915
1930
Thomson (JJ) discovers electron
Balmer, Rydberg relate emission
spectrum lines to counting number
“n”
Electron Theory
Bohr Model
proposed
Heisenberg
Uncertainty Principle
Davisson/G.P. Thomson
Schrödinger
(irony!): electron
Wave Model
diffraction
Pauli
Exclusion
Principle
Content Highlights
• Observation of spectra without explanation
(Kirchoff/Bunsen)
• Balmer/Rydberg develop a mathematical
relationship without an explanation
• Quantization of energy required as a
concept
Quantum Mythbusting
• There was no “ultraviolet
catastrophe”
– Term not coined until 1911
– There was a disagreement
between theory and
observation, but no
catastrophe
• Planck did not quantize light
– Einstein did this later
Content Highlights, con’t
• Wave-Particle Duality
– Einstein suggests that photoelectric effect
results can only be explained if light behaves
like a particle
• Quantum Indeterminacy
– Objects exist in indetermined
states until observed
– Schrödinger’s Cat
– Ghostbusters
Choose The Form!
Content Highlights, further!
• Hund’s Rule = Monopoly houses
• Balmer/Rydberg develop a
mathematical relationship
without an explanation
• Quantization of energy required
as a concept
Simulations
Bohr Model Applet (web)
Electron Model Comparison (requires Java –standalone/web)
Orbital Viewer (standalone, downloadable)
Labs
• Hydrogen Spectrum Lab (h/t Mike Jones, Pisgah HS)
• Flame Tests
– DON’T use petri dishes, spray bottles, dry
salts (safety/toxicity concerns)
– Try instead
• Wooden splints (steal from coffee shops); soak in
• Aqueous solutions of salts (plus a little MeOH):
LiCl, KCl (if you have cobalt glasses), CaCl2, SrCl2,
boric acid (for green; I avoid Ba salts)
– Fireworks glasses (rainbow glasses)
The Atomic Theory Org Chart
It’s not just what you know, but
apparently whom
JJ Thomson
Robert Millikan
Manchester
Cambridge
Ernest Rutherford
Copenhagen
Max Born
Niels Bohr
Werner
Friedrich Wolfgang Heisenberg
Hund
Pauli
Henry
Moseley
Louis
de Broglie
Hans
Geiger
Ernest
Marsden
Max
Planck
Albert
Einstein
Göttingen
James
Chadwick
Berlin
Philipp
Lenard
Erwin
Schrödinger
Resources
Powerpoint presentations:
• Early Atomic Structure
•The Bohr Model
•The Schrödinger Model (quantum numbers by element)