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CHEMISTRY 351

CHEMISTRY 351. Fall 2005. ORGANIC CHEMISTRY. Professor Donald Pavia. Lecture : MTWF 9 SL 130. http://atom.chem.wwu.edu/dept/wwuchem.html. CHEMISTRY WEB SITE. “Course Materials” “Pavia” “Chem 351” . COURSE WEB SITE.

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CHEMISTRY 351

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  1. CHEMISTRY 351 Fall 2005 ORGANIC CHEMISTRY Professor Donald Pavia Lecture : MTWF 9 SL 130

  2. http://atom.chem.wwu.edu/dept/wwuchem.html CHEMISTRY WEB SITE “Course Materials” “Pavia” “Chem 351” COURSE WEB SITE http://atom.chem.wwu.edu/dept/facstaff/pavia/351pavia.html

  3. SOME ADVICE ON STUDYING FOR ORGANIC CHEMISTRY

  4. missing material STRUCTURE OF KNOWLEDGE IN ORGANIC CHEMISTRY Builds like a pyramid balanced on its point.

  5. If something is missing ….. The whole structure collapses !!!

  6. MATERIAL IN THIS COURSE IS CUMULATIVE STUDY TO UNDERSTAND THE MATERIAL The material keeps building on itself. ANYTHING THAT YOU DO NOT MASTER WILL COME BACK TO HAUNT YOU LATER You literally cannot forget anything in this course. WE WILL BUILD ON EARLIER TOPICS TO DEVELOP NEW ONES

  7. IF YOU DON’T UNDERSTAND SOMETHING ….. GET HELP AS SOON AS YOU CAN See me after class, during office hours, or make an appointment. DO AS MANY PROBLEMS AS YOU CAN FIND TIME FOR IN YOUR SCHEDULE Active learning is more effective than passive study. Doing problems really cements your understanding it requires you to apply what you learn. THE END-OF-CHAPTER PROBLEMS ARE THE MOST HELPFUL

  8. STRANGE BUT TRUE We retain : 90% of what we say as we do a thing 70% of what we say as we talk 50% of what we see and hear 30% of what we see 20% of what we hear 10% of what we read ACTIVE PASSIVE ….. a psychological study

  9. DON’T GET BEHIND !!!! Although the very early material is easy, or even simple review material for you, things will get more difficult very quickly.

  10. “Every day you don’t practice means you’re a day farther from getting good.” Ben Hogan, golf champion “The greatest reward for doing is the opportunity to do more.” Jonas Salk, inventor of polio vaccine “Success comes before work only in the dictionary.” Anonymous “I hear and I forget, I see and I remember, I do and I understand.” Anonymous “If you’re are going through hell, keep going.” Winston Churchill

  11. QUICK REVIEW OF GENERAL CHEMISTRY STUFF

  12. ATOMIC STRUCTURE AUFBAU PRINCIPLE - Hund Rule - Pauli Exclusion Principle ELECTRONIC CONFIGURATIONS OF ATOMS Review in your general chemistry text is suggested Ebbing and Gammon : Chapters 7 and 8

  13. 3d 4s 3p 3s 2p 2s 1s CORRECT ORDER OF FILLING FOR THE FIRST THIRTY ATOMS E N E R G Y

  14. Electronic Configurations of First Eleven Elements H 1 1s1 [CORE] VALENCE SHELL He 2 1s2 Li 3 1s22s1 [1s2]2s1 Be 4 1s22s2 [1s2]2s2 B 5 1s22s22p1 [1s2]2s22px1 C 6 1s22s22p2 [1s2]2s22px12py1 N 7 1s22s22p3 O 8 1s22s22p4 F 9 1s22s22p5 Ne 10 1s22s22p6 Na 11 1s22s22p63s1 [1s22s22p6]3s1

  15. LEWIS DOT SYMBOL VALENCE ELECTRONS . Be . CORE Be [1s2]2s2 [CORE] VALENCE ELECTRONS

  16. D Block S and P Blocks Transition Metals “B group” elements Main Groups or “A group” elements 1A 2A 3A 4A 5A 6A 7A 8A (1) (18) He H PERIODIC TABLE 1 (2) (13) (14) (15) (16) (17) Be Li N O F Ne B C 2 Mg Na P Al Si S Cl Ar 3 (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) Ca K Sc Ti V Ga Ge As Se Br Kr Co Cr Mn Fe Ni Cu Zn 4 In Sn Sb Sr Ag Cd I Xe Rb Y Zr Nb Mo Tc Ru Rh Pd Te 5 Cs Ba Lu Hf Ta Ir Pt Au Hg Pb Bi At Rn W Re Os Tl Po 6 Lr Fr Ra Rf Db Sg Bh Hs Mt Ds Uuu Uub Uut Uuq Uup Uuh Uus Uuo 7 lanthanides La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb actinides Ac Th Pa U Np Pu Am Cm Bk Cf Fm Md No Es The traditional system designates groups as A (main) or B (transition). The modern system (IUPAC) now uses 1 - 18 in sequence.

  17. Table 1-2 in text The A groups are regular.

  18. . . H H A SIMPLE COVALENT BOND A pair of electrons is shared between the two bonded atoms.

  19. A SIMPLE COVALENT BOND Bonded pair H H

  20. A LEWIS DIAGRAM .. (note use of lines for bonds) H O H .. COVALENT BONDS CONSTRUCTED FROM LEWIS DOT SYMBOLS .. . . . . H O H ..

  21. METHANE DOTS AND CROSSES METHOD H CH4 . x . . H C H x x x . H

  22. DRAWING CONVENTIONS 1. A shared pair (bond) is drawn as a line. • C O ( not as C:O ) 2. An unshared pair is shown as a pair of dots. N : 3. The diagram includes formal charges (later). .. + H O H USE THESE H

  23. . .. .. . . O C O .. .. . .. .. O C O .. .. CARBON DIOXIDE . .. .. . . . . . . O C O .. .. .

  24. “DOTS AND CROSSES” This method of forming Lewis Diagrams could facetiously be called the “Dots and Crosses” method. This method has real limitations. We will learn an alternate method, which is more general, in the next set of slides.

  25. . x DOTS AND CROSSES DON’T WORK WELL FOR LARGE MANY-ATOM MOLECULES …. WE NEED A DIFFERENT METHOD WHICH FOLLOWS ……..

  26. CONSTRUCTING LEWIS DIAGRAMS: A NEW METHOD

  27. 1. Count and add the number of valence electrons contributed by each atom of the molecule or ion. . . . : : ( H + O + H) = 8 electrons for water (H2O) . 2. Determine the arrangement of the atoms (skeleton) for the molecule or ion. H-O-H This you must obtain from intuition, some rules, or information given by the instructor. 3. Subtract the electrons used in each of the skeletal bonds ( 2 electrons each bond ) from the total. (8 - 4) = 4 remaining for H2O DRAWING LEWIS DIAGRAMS 4. Assign the remaining electrons following the Lewis Rules.

  28. 1.OCTET RULE:In a completed Lewis Diagram, Period 2 or Period 3 atoms will have a completed octet :( 8 electrons). The term duet is not formally used Hydrogen atoms will have a “duet” : ( 2 electrons). 2. BONDS. Bonds are made by sharing a pair of electrons between two atoms. Single Bonds ( 1 shared pair ) Double Bonds ( 2 shared pairs ) Triple Bonds ( 3 shared pairs ) are all allowed in constructing a Lewis Diagram. Hydrogen, is always singly bonded. LEWIS RULES (a reminder)

  29. N: 3.ELECTRON PAIRS. Electrons not involved in forming bonds (non-bonded or unshared electrons) are arranged in pairs. 4.CORRECTNESS. The final structure must have the correctnumber (total) of valence electrons. LEWIS RULES ...... continued

  30. REVIEW OF METHOD 1. Determine the total number of valence electrons in the molecule or ion. 2. Determine the arrangement of the atoms (the skeleton). 3. Subtract the electrons used in the skeletal bonds ( 2 electrons each bond ) from the total. 4. Assign the remaining electrons following the Lewis Rules (octets, duets, bonds, pairs etc.). 5. Check that the total number of electrons is correct ( count them ! ). Do CO2 or H(CO)Cl

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