office hours changed (today only!) 11:00 am-12:30 pm exam #3 results chapter 8 homework posted...
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•Office Hours changed (today only!)
•11:00 am-12:30 pm•EXAM #3 Results•Chapter 8
•Homework posted•Today’s Topic: Lewis Structures
November 11, 2009
Bond Types
1. Ionic Metal & Nonmetal
Charged atoms- based on electrostatic attraction
2. Covalent1. Nonmetal & nonmetal
2. Uncharged atoms- electrons are “shared”
3. e- - p+ attractions and p+- p+ or e- - e- repulsion between atoms
Metallic
Special type of covalent bonding for solids
Balance of Forces in Covalent Bonding
Bond will form when the balance of forces favors bonding (attractions > repulsions)
Please make your selection...
1. Choice One2. Choice Two3. Choice Three4. Choice Four5. Choice Five6. Choice Six7. Choice Seven8. Choice Eight
What do those lines and dots mean?
A Lewis structure for a molecule describes the arrangement of electrons
Only valence electrons used Lines=bonds Dots= electrons that aren’t in a bond
Rules for Drawing Lewis Structures
1. Write the skeletal structure2. Add up the total # of valence electrons3. Draw a bond between the central atom and each
surrounding atom4. Add lone pairs to the outer atoms to complete their
octets5. Add remaining electrons to central atom6. If central atom does not have an octet, “borrow”
electrons from other atoms (make double/triple bonds)- DO NOT ADD ELECTRONS (F and Cl do not form multiple bonds; C, N, O, P, and S do)
7. Sometimes you can’t complete an octet (B and Be)