Transcript Chemistry 100 - University of Illinois at Urbana–Champaign

To Do…
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Electronic homework (Lon-Capa)
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Friday:
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HW6 Type 1 due Monday, April 21 by 7 pm;
HW6 Type 2 due Wednesday, April 23 by 7 pm
Text homework.
Lab write-up.
Discuss exam
Tuesday’s lecture: Chapter 11
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Overall goal:
Atomic Structure
Chemical Bonding
3D Molecular Structure
Molecular Properties
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Big Ideas – Periodic Table
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Originally arranged by atomic
mass (protons not discovered).
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See Co & Ni; Te & I.
Separated as “metals” and
“nonmetals”
(appearance/properties)
 Chemical reactivity
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Big Ideas – Periodic Table
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The closer together the
elements on the periodic table,
the more chemically alike they
are.
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Especially true for elements in
the same column.
“Missing” elements were
predicted.
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Big Ideas – Models
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Models are not reality.
We use different models for
different reasons.
A model should be as simple as
possible, but not simpler (Einstein)
To answer more questions, the
model must be more complex.
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Various Atomic Models (Ch. 4)
Dalton: Indivisible atoms
 J.J. Thomson: Atoms emit tiny negative particles.
(Therefore atoms not indivisible!)
 William Thomson (Lord Kelvin): formulates the
Plum Pudding Model.
 Rutherford: Some α-particles bounce back when
shot at atoms. (There is a concentration of mass
with a positive charge in the atom.)
http://www.youtube.com/watch?v=5pZj0u_XMbc
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Figure 11-1 p239