Chem 125 Lecture 1 9/5/00 Projected material

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Chem 125 Lecture 19/5/00Projected material
This material is for the exclusive use of Chem
125 students at Yale and may not be copied or
distributed further. It is not readily
understood without reference to notes from the
lecture.
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Enter on the white card in this order (no need to
write categories)
Name (pronunciation hints if necessary) Prefer
to be Called (e.g. Jay, not Jethro) Hometown
with zip code E-mail Name of your best science
teacher (with subject) Prospective major(s)
Put comments or questions on back.
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Exam Dates
9 lectures Sept 26 9 lect Oct 19 9 lect Nov.
12 10 lect Dec 17
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HELP !
Other Chem 125 students! Alumni
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Problems
For Friday 1)
Which two class members live nearest you? 2)
What are the three most common items of
advice from course veterans? 3) Send e-mail to
ivar.mcdonald_at_yale.edu
For Monday (Problems from Text - Ch 2 1,2,
4a-e, 5a-e) 1) Are Lewis Structures correct? 2)
What do they show?
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How do you know?
John McBride (age 3)
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How do you know?
John McBride (age 29)
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Finger Writes
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Shows Joshua
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Asks question of Class
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Class
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Do not suppose that I was a very deep thinker,
or was marked as a precocious person. I was
a very lively imaginative person, and could
believe in the "Arabian Nights" as easily as in
the "Encyclopaedia." But facts were important to
me, and saved me. I could trust a fact, and
always cross-examined an assertion. So when I
questioned Mrs. Marcet's book by such little
experiments as I could find means to perform, and
found it true to the facts as I could understand
them, I felt that I had got hold of an anchor in
chemical knowledge, and clung fast to
it. Michael Faraday, 1858
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Learn from science that you must doubt the
expertsScience is the belief in the ignorance of
experts.
Richard Feynman (to National Science Teachers
Assn 1966)
When someone says science teaches such and
such, he is using the word incorrectly. Science
doesn't teach it experience teaches it.
Because he is an expert?
If they say to you science has shown such and
such, you might ask, "How does science show it -
how did the scientists find out - how, what,
where?"
Not science has shown, but this experiment,
this effect has shown.
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Munowitz (fall 73)
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Munowitz review facts
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Budiansky Cover
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How do we know?
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What are the most importantTOOLS?
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G.N. Lewis(1875-1946) hisCubic Octet
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Lewis on running board
G. N. Lewis
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Octet "Explains" Periodicity, Electron Transfer
(1902)
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Octet Predicts Shared Pair Bonding
?
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G.W. and Robert Robinson (1917)
Partial Valences to explain trivalent and
pentavalent N???
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Levitator by Martin Simon (UCLA)
Eppur sta fermo
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Frog
Thanks to Prof. André Geim
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Earnshaw's Theorem(1839)
In systems governed by inverse-square force
laws there can be no local minimum (or
maximum) of potential energy.
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Visualizing Earnshaw - Coulomb's Electrostatics
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A positive particle has a local maximum or
minimum of energy only at the location of another
charged particle, never in free space.
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Earnshaw's Theorem
In systems governed by inverse-square force
laws there can be no local minimum (or
maximum) of potential energy.
The only stationary points are saddle points.
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"I have ever since regarded the cubic octetas
representing essentially the arrangementof
electrons in the atom" G. N. Lewis (1923)
Was Lewis ignorant of Earnshaw's Theorem?