Wednesday, November 26, 2008

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NO${}_3^-$ doulbe-bonds stronger&shorter than single-bonds.
Exceptions to octet-rule(90%)
1. odd# of valence electrons.  ex.  CH${}_3\cdot$ methyl radical
2. (less than 8) group 13 B Ga Al  ex. BF${}_3$ needs 32  have 24 bondingelectrons 8 B${}^[-]$ -> B${}^[0]$ not like NO${}_3^-$
3. (more than 8) valence share expantion (expanded shell; has d-shell to accomodate more than 8 electrons)  Ex1.  PCl${}_5$ phosphorus pentachloride needs 48  have 40 bondingpair 4  Ex2. Iodine tetrafluoride IF${}_4^-$ needs 40 have 35+1 bondingelectron 4

Ionic bonds.  Sodium Chloride IE-IA is equal to elecronic forces around 10A(ngstrom)
IE Ionization Energy.   EA Electron Affinity



Lec 13 | MIT 5.111 Principles of Chemical Science, Fall 2005

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