1. Dr. S. M. Condren Chapter 10 Molecular Structures

2. Dr. S. M. Condren

3. What is the “shape” of the molecule? How are valence electrons in a molecule distributed among the orbitals? What are the shapes of these orbitals? What order are they occupied?

4. Dr. S. M. Condren Molecular Geometry VSEPR Theory Valence Shell Electron Pair Repulsion Theory draw Lewis electron dot structure count the number of bonding electron pairs about central atom (double and triple bonds count as one pair for shape prediction) count the number of lone pairs of electrons match electron pair information to shapes

5. Dr. S. M. Condren

11. Shape: PCl 3 Lewis Electron Dot Structure...... :Cl  P : Cl:...... :Cl:.. 3 bond pairs 1 lone pair=>AB 3 E trigonal pyramidal shape

12. Dr. S. M. Condren Shape: IF 5 Lewis Electron Dot Structure.... : F : : F :...... : I : F :...... : F : :F :.... 5 bonds pairs 1 lone pair=> AB 5 E Square pyramidal shaped

13. Dr. S. M. Condren Shape: IF 4 -1 Lewis Electron Dot Structure.... -1 : F : : F :...... : I : F :...... : F :.. 4 bond pairs 2 lone pairs=> AB 4 E 2 square planar shape

14. Dr. S. M. Condren Shape: SO 3 Lewis Electron Dot Structure.. : O : S : : O :...... : O :.. 3 bond pairs 0 lone pairs=>AB 3 trigonal planar shape

15. Dr. S. M. Condren What would be expected to be the shape of chloroform, CHCl 3 ? “see-saw” square planar tetrahedral

16. Dr. S. M. Condren http://www.colby.edu/chemistry/OChem/DEMOS/Orbitals.html

17. Dr. S. M. Condren

20. What would be the name of the hybrid orbitals created by joining 1s type, 3 p type and 2 d type orbitals? spd sp 3 d 2 s 3 p 2 d

21. Dr. S. M. Condren Sigma Bond  Bond with the greatest electron density on a line connecting the atomic nuclei s-s typep-p types-p type s-sp 3 types-sp 2 type s-sp type p-sp 3 typep-sp 2 type p-sp type sp 3 - sp 3 typesp 2 -sp 2 typesp - sp type etc., including all combinations of s, p, d, and hybrid orbitals

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24. Pi Bond  Bond with the greatest electron density above and below a line connecting the atomic nuclei p-p type

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35. Water, H 2 O, and methane, CH 4, have very similar molar masses yet the boiling point for water is approximately 200 o C higher than that for methane. The higher boiling point is due to: hydrogen bonding in water polarity of water molecules both of the above none of the above

36. Dr. S. M. Condren Carbon monoxide, CO and carbon dioxide, CO 2, are linear molecules. Which one is the polar molecule: CO CO 2

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38. http://mrsec.wisc.edu/edetc/DNA.htm

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41. In DNA, thymine always links to adenine and cytosine always links to guanine. This is due to: one is a base and the other an acid number of hydrogen bonds each can form one is attached to a sugar and the other a phosphate

42. Dr. S. M. Condren