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Prerequisites: 112, D/C non-majors/majors

CHEM 333. √. Prerequisites: 112, D/C non-majors/majors. synthesis. TODAY. Contact information. Identify a seat (seating chart will be circulated) Lecture Recitations start this week - work problems, discuss concepts, take quizzes Prerequisites and other things Start Chapter 1.

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Prerequisites: 112, D/C non-majors/majors

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  1. CHEM 333 √ Prerequisites: 112, D/C non-majors/majors synthesis

  2. TODAY Contact information Identify a seat (seating chart will be circulated) Lecture Recitations start this week - work problems, discuss concepts, take quizzes Prerequisites and other things Start Chapter 1 1st labs meet this week Non-major’s lab 331L Major’s lab 333L

  3. Professor John H. Dawson, GSRC Room 410, 7-7234, dawson@sc.edu Lecture: TuTh 5:00-6:15 PM PSC Room 002 Office Hours: M-Th 3:00-3:45 PM, before/after class and by appointment Lecture Recitation Sections: Section 1, Room PSC 115, Fri 1:25-2:15 PM, Vibha Gupta Sect 2, Room PSC 203, Thurs 12:30-1:20 PM, Lisa Brodhacker Sect 3, Room PSC 214, Fri 1:25-2:15 PM, Avneesh Saini Sect 4, Room PSC 214, Thurs 2:00-2:50 PM, Andrew Lee

  4. PSC002 Back Door J I H G F E D C B A 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Front Door front desk screen-white boards choose your “assigned seat”

  5. Prerequisites and other Things • You must have passed Chem 112 with a C/D (major/non-major) or better • to be in Chem 333. • You must be registered for the course • unless you are making up an incomplete (I). • If you are making up an incomplete, see JHD • Grades will be posted by the last four numbers of your SSN • Or • Give me an “alias” set of four numbers • to use in place of the last four numbers of your SSN

  6. Text: Organic Chemistry, 4th ed. Brown, Foote, Iverson (3rd ed.?) Also: Study Guide and Problems & models are strongly recommended! Consider other aids: Organic As a Second Language OWL Different organic texts Others? Exams: Jan 31, Mar 2, Apr 11 Final: May 1, 5:30 PM

  7. Chapter 1 COVALENT BONDING & SHAPES OF MOLECULES 1.1Electronic Structure of Atoms 1.2 Lewis Model (Octet Rule, Formal Charge) 1.3 Functional Groups 1.4 Bonding Angles and Shapes of Molecules 1.5 Polar and Nonpolar Molecules 1.6 Resonance 1.7 Quantum or Wave Mechanics 1.8 Molecular Orbital & Valence Bond Theory, CovalentBonds, Hybridization (sp3, sp2, sp) SUMMARY and OVERVIEW 1-11 1

  8. Organic Chemistry: the study of compounds of carbon Li Be BC N O F Ne WHY is CARBON SPECIAL? CARBON - is small, intermediate electronegativity - forms strong bonds with itself/other atoms C-C 83.1 kcal/mole 2X as strong as: N-N, O-O, Si-Si -forms strong double and triple bonds (to C or other atoms) Over 10 million structures identified; ~1000 new/day!

  9. Recall the Structure of an ATOM: (neutrons +protons(+)) nucleus electrons(-) 1833 to 1 mass: quantum mechanics: motion of e’s particle & wave like electrons confined to regions of space: shells (principle energy levels)

  10. each shell can hold 2n2 electrons Electronic Structure of Atoms

  11. ground stateelectronic configuration (atoms or molecules) Aufbau Principle: fill orbitals lowest to highest energy Pauli Exclusion Principle: 2 electrons per orbital, spins paired Hund’s Rule: degenerate orbitals, 1 electron in each then create a pair

  12. Valence Shell Hund’s Rule Pauli & Lewis next level closed shell (s) 3 (p) E 2 (s) 1 (s) Li Be B C N O F Ne H He writing electronic configuration

  13. electronic configuration No. of e's 1 H 1s1 2 He 1s2 3 Li 1s2 2s1 4 Be ……. 5 B ……… 6 C 1s2 2s2 2p2 7 N etc. Electronic Configuration What is the electronic configuration of OXYGEN? 1s2, 2s2, 2p4

  14. Lewis Structures (Gilbert N. Lewis) Valence shell: the outermost electron shell Valence electrons: electrons in valence shell electrons used to bonds • Lewis structure: • atom symbol = nucleus + inner e- • dots represent valence electrons

  15. Lewis Structures • Table 1.4 Lewis Structures

  16. electrons to complete a shell H He +1 0 Li Be B CN O F Ne -1 -2 -3 ±4+3 +2 +1 0

  17. - loss or gain of valence electrons -share electrons to fill shells or Bonding extremes - IONIC or COVALENT ionic bonds ? covalent bonds ?

  18. Electronegativity Electronegativity: a measure of an atom’s attraction for the electrons it shares with another atom • Pauling scale • increases left to right in a row • increases bottom to top in a column

  19. less than 0.5 covalent + - 0.5to1.9 polarcovalent greater than 1.9 ionic Electronegativity Table 1.6 Classification of Bonds electronegativity difference bond type H3C-H 2.5 2.1 Na+-Cl 0.93 3.16

  20. Chapter 1 COVALENT BONDING & SHAPES OF MOLECULES 1.1 Electronic Structure of Atoms 1.2 LewisModel (Octet Rule, Formal Charge) 1.3 Functional Groups 1.4 Bonding Angles and Shapes of Molecules 1.5 Polar and Nonpolar Molecules 1.6 Resonance 1.6 Quantum or Wave Mechanics 1.7 Molecular Orbital & Valence Bond Theory, CovalentBonds, Hybridization (sp3, sp2, sp) SUMMARY and OVERVIEW 1-11 1

  21. Lewis (electron dot) structures covalent molecules and ions Determine the number of valence e's in molecule (ion) Ions - add/subtract 1 electron for -/+ charge Determine an order of attachment Connect atoms with single bonds. Arrange remaining e's in pairs so each atom has a complete shell. Pairs of e's - shown as “ -“; nonbonding e's as dots Shared e's can be single, double or triple bonds charges?

  22. Charge on an atom/molecule is formal charge, i.e.H3O+, HO- To assign Formal Charge: 1. Write correct Lewis structure 2. Assign each atom: all non-bonding e'shalf the shared e’s 3. Compare this number to valence e-s in neutral unbonded atom.

  23. number of valence electrons 1/2 of shared electrons unshared electrons - = + Formal Charge on an atom Formal Charge

  24. 0 +1 -1 valence of N = 5 [2 + 1/2(6)] = 5 e’s belong to the first N = 5- 5 = 0 charge e’s belong to the 2nd N = [1/2(8)] = 4 5 - 4 = +1 charge [4 + 1/2(4)] = 6 e’s belong to the 3rd N = 5 - 6 = -1 charge

  25. Exceptions to the octet rule: Group 3A - B, Al - due to valence, form 3 bonds - stable but reactive 3rd row+ elements - e.g. S - can share more than 8 e’s

  26. Recall Formal Charge Lewis structures - filled shells

  27. Chapter 1 COVALENT BONDING & SHAPES OF MOLECULES 1.1 Electronic Structure of Atoms 1.2 LewisModel (Octet Rule, Formal Charge) 1.3 FunctionalGroups 1.4 Bonding Angles and Shapes of Molecules 1.5 Polar and Nonpolar Molecules 1.6 Resonance 1.6 Quantum or Wave Mechanics 1.7 Molecular Orbital & Valence Bond Theory, CovalentBonds, Hybridization (sp3, sp2, sp) SUMMARY and OVERVIEW 1-11

  28. Functional Groups: atom(s) bonded to C having characteristic properties Determine: reactions properties basis of nomenclature & classification

  29. methyl,1o, 2o, 3o see Hs & Cs here 1o, 2o or 3o by Hs on N Functional Groups: atom(s) bonded to C having characteristic properties alcohols: hydroxyl group amines:amino group

  30. amines: 1o, 2o, 3o Aldehyde / Ketone (carbonyl group C=O) Carboxylic Acid(carbonyl + hydroxyl group-CO2H) Carboxylic Amide- (carbonyl + amine -C(O)N-) Carboxylic Ester - (carbonyl + alcohol -CO2R) FUNCTIONAL GROUPS alcohols: (hydroxyl group, sp3-> C-O-H) 1o, 2o, 3o Others ethers, halides, etc. Formulas: complete, condensed and/or line

  31. VSEPR - electrons (e-) in bonds/orbitals repel each other  4 groups/bonds repulsion yields a tetrahedral shape ~109.5o  3 bonds repulsion yields a trigonal shape ~120o  2 bonds repulsion yields a linear shape 180o eg: CH4 or NH3, HCO2H, CO2

  32. - - - + + Polar and Nonpolar Molecules (1) has polar bonds Polar if: (2) if the arrangement is “irregular”

  33. Resonance - sometimes aLewis formula is not an accurate representation. e.g. the anion of formamide:

  34. note: charges and double bonds Resonance - sometimes aLewis formula is not an accurate representation. Compound w/ >1 Lewis structure but same connectivity = resonance Resonance hybrid - real, average - connect contributors with

  35. source: Resonance- some Lewis formulas inaccurate representation Create new contributing structures by arrows - e's move from source to need! non-bonding,  -bond, p-orbital e's 1. Flow from an atom to an adjacent bond 2. Flow from a bond to an adjacent atom

  36. Writing acceptable resonance contributing structures 1. Contributing structures-same # valence e-s. 2. 2nd row elements - no more than 8 e-s, 3rd row up to 12e-s 3. Nuclei don’t change positions 4. All contributing structures should show the same number of paired and unpaired electrons

  37. Writing acceptable resonance contributing structures 1. Same number of valence e-s 6 4 7 7 4 6 2. 2nd row 8; 3rd row > 8

  38. Rules to write acceptable resonance contributing structures 3. All nuclei remain in the same positions valid

  39. this is “OK” Rules to write acceptable resonance contributing structures 4. Same number of paired & unpaired e-s. X not valid e-pairs have decreased

  40. Which resonance contributing structure(s) is(are) IMPORTANT 1. complete octets contribute more. 2. more covalent bonds - contribute more. 3. charge separation less important. 4. (-) on more electronegative atom, (+) on electropositive is more important.

  41. http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/FG12_05.JPGhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/FG12_05.JPG

  42. Orbitals for sp2 hybridization 3 sp2 and p orbitals on axis hybrid

  43. 3 sp2 and p orbitals on axis

  44. pz s two sp hybrid orbitals sp sp px py two sp hybrid orbitals pz py sp HYBRIDIZATION

  45. End of Chapter 1  2

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