Wednesday, March 30, 2005

Lecture 003: Lewis Structures

We reviewed the Lewis Dot structures of H2, F2, O2, N2, CH4, CO2, BF3, NH3, CO and SO. And then the fire alarm went off and we had to rush out.

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Lecture 002: Electronic Configuration

We reviewed the electronic configuration of the first 10 elements using the Pauli Exclusion Principle and Hund's Rule. Introduced covalent and ionic bonding.

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Tuesday, March 15, 2005

LEWIS DOT APPROACH TO MOLECULAR STRUCTURE

LEWIS DOT APPROACH TO MOLECULAR STRUCTURE

Predicts geometry, polarity, basicity, etc.
ONE COVALENT BOND = 2 SHARED ELECTRONS
1) Count total number of electrons available (by the row in the periodic table, e.g. C=4, N=5, O=6, F=7, Ne=8)
2) Find out how many electrons are needed: 8 for each C,N,O,F and related elements 2 for H
3) [(2)-(1)] / 2 = number of bonds in the molecule
4) After placing bonds, complete octets
5) Count electrons around atoms and place charges
6) Make sure total charge, total number of electrons and octets work out

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