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Romantic Atomic Love Affairs?

Romantic Atomic Love Affairs?. http://www.youtube.com/watch?v=6nclUZoouHQ. http://www.youtube.com/watch?v=L4w1Mp6Mce4&feature=related. Trivia: besides LSU, what university sings Hey Baby at games?. Love isn’t always romantic. Hotel Californian—Santa Barbara

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Romantic Atomic Love Affairs?

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  1. Romantic Atomic Love Affairs? http://www.youtube.com/watch?v=6nclUZoouHQ http://www.youtube.com/watch?v=L4w1Mp6Mce4&feature=related Trivia: besides LSU, what university sings Hey Baby at games?

  2. Love isn’t always romantic. Hotel Californian—Santa Barbara http://www.edhat.com/img2/beats/HC-006.jpg Atomic dating is more often needy, fast and brutal, the surroundings messy and cheap.

  3. Electrons exist in orbitals. We can think of these as Bohrbits…Standing Waves in 3 Dimensions. Of course 2-D is easier to see. Sand on a kettle drum! By this analogy, electrons would be where sand isn’t (sand sits at the nodes).

  4. Bohrbits: More energy  can afford more complexity. These are standing waves in three dimensions. http://chemlinks.beloit.edu/Stars/images/orbitals.jpg

  5. 1s 2s 2p 3s 3p 3d 4s 4p CrayolaPeriodic Table

  6. Coulomb's Law: opposites attract.  F Fast, high-E electron Slow, low-E electron - - + + Small radius Big radius

  7. Electron Configurations: how are electrons partitioned according to energy? Example:  Calcium = 1s22s22p63s23p64s2 There are all kinds of mnemonic devices for this (see your textbook, and also the notes or website) but the easy solution is: Just follow the periodic table!  

  8. But first a romantic (?) Southern riddle about Billy Joe and Annabelle Leigh* *With apologies to Edgar Allen Poe

  9. Mendeleev was even able to predict!One example: Eka-silicon (Ge) Predicted 1871Discovered 1886 At.Wt. 72 72.6 Color gray gray Density 5.5 5.5 (g/cm3) Oxide EsO2 GeO2 Chloride EsCl4 GeCl4 B.P. Chloride Under 100 84 (oC)

  10. Meyer also saw periodicity. His version was physical—we can imagine it was size-based. But how do we know this???

  11. Other things that repeat • Density • Boiling point • Melting point • Ionization energy (e.g., how hard to yank an electron away) • Which way do you think ionization energy goes? 

  12. It is hard to steal electrons from the elements on the right side of the periodic table.

  13. Electronegativity • Define: the "desire" an atom has for electrons • All atoms desire electrons—a matter of degree • Atoms at the very right of the table (with completely full shells) don't want to acquire more electrons. • Atoms near the right of the periodic table (with almost full shells) want electrons very badly. We say these atoms (like chlorine or fluorine) are electronegative. • Atoms on the left are glad (well, not too sad) to give them up.

  14. 1. The most electronegative atom is F.2. Electronegativity is yet another thing that repeats.

  15. Major groups: most elements are metals!

  16. Group VIII are the Noble Gases • Too regal to react • All end in s2p6 *** • Example: Argon = • 1s22s22p63s23p6 • ***Except He (1s2) “We are not amused.”

  17. Group I and Group II = Metals • Alkali metals, example Sodium  • not greedy at all—ready to lose electrons—its last electron was high-energy and “out there” ready to get stolen! Na = 1s22s22p63s1 Mg = 1s22s22p63s2

  18. Group VII = Halides • Example: Chlorine • very greedy: • Chlorine: 1s22s22p63s23p5

  19. Transition metals: electrons galore, but not desperate to get rid of them—lots of protons to hold electrons where they are. • exampleIron:  • --Sea of electrons • --certainly enough electrons to conduct electricity • --but not desperate to get rid of them Fe: 1s22s22p63s23p64s23d6

  20. Nonmetalsexample Carbon:  share and share alike C: 1s22s22p2 Si: 1s22s22p63s23p2 Metalloidsexample Silicon:  can be "doped" to behave a little bit like metals; semiconductors http://1.bp.blogspot.com/_Zx0SO3YqO2g/TCGo5P6JawI/AAAAAAAAAA8/sdLBzI2Fep4/s320/Transistor.jpg

  21. Octet Rule: Chemistry often follows the rule of 8’s: Atoms try to end in s2p6 • Rule of 8's: the s2p6 configuration is very stable: noble gases • Atomic jealousy: every atom wants to look like s2p6--e.g., Na   Na+1 • Why?---What is special about s2p6? • Is there an easy answer?

  22. Who is more likely to encounter extra-terrestrial life, you or one of these people?

  23. We repeat: electrons that are “out there” are more energetic…and more likely to be found by other atoms. Fast, high-E electron Slow, low-E electron - - + +

  24. Valence Electrons = Energetic, Outer Electrons The active electrons are called valence electrons.  Inner shell electrons are “screened”—not so visible to alien atoms. Examples:  Potassium has 19 electrons, but only 1 valence electron Carbon has 12 electrons, but only 4 valence electrons The number of valence electrons = the Group Number!

  25. Lewis Dot Structuresshow just the valence electrons By Octet rule, Chorine would rather be this anion: -1

  26. Preview Cl2, O2, N2 examplesNa & Br exampleDon’t worry, we’ll get LOTS more covalent examples later!

  27. Coulomb's Law:  Can we explain Meyer’s size trends, ionization energies & electronegativity? F Compare Cl and Na Cl has q+ = 17 Na has q+ = 11 Cl pulls harder on its electrons than Na. So….Cl will steal from Na…and put the electron in a smaller orbital, too, closer to nucleus.

  28. See? Cl is smaller. And Ar is smaller still.

  29. Then why does K get bigger again? More energy! K’s last electron has energy quantum number n=4 The last electron captured by the K nucleus was a fast, energetic one. The last electron placed determines what the atom wants to do.

  30. Types of Bonds: Quick Intro

  31. Ionic Bonds: back to the legend of Billy and Annabelle Leigh Define: An ion is an atom or molecule that carries a net charge. Cation = + ion (lost an electron) Anion = - ion (gained an electron) Anions attract Cations

  32. Billy Joe pulls a wig out of his pocket, gives to Annabelle Leigh. Then they can snuggle. Billy Joe Cation Annabelle Leigh Anion

  33. Why do ions form? Ions form generally because atoms seem to want to "look like" noble gases. Na  Na+ + e- Note balance of charge! No charge on left side of arrow. None on right.

  34. Why do ions form? Ions form generally because atoms want to "look like" noble gases. Cl+ e-Cl- Note balance of charge! -1 charge on left side of arrow. -1 on right.

  35. The public debt of the U.S. is calculated to the penny! March 1, 2005: $7,701,629,503,518.55 October 5, 2011: $14,837,099,271,196.71 Your share: about $47,400 It goes up by about $13/day/person http://www.usdebtclock.org/

  36. + + Electrons & Protons do an even betterbalancing act. Balance to better than… 1 : 1,000,000,000,000,000,000,000,000 Fcoulombic for 1% imbalance of charges would lift Earth in its own gravity (from Feynman Lectures)

  37. Isoelectronic = Same Electronic Configuration Ne / Na+ / Mg++

  38. A Note About Notation Mg++ means the same thing as Mg2+ Either is very different from something like Mg2+ (not a normal form of magnesium) DOWN (SUBSCRIPTS) =  how many atoms UP (SUPERSCRIPTS)  = how many charges

  39. Left subs/supers vs. Right subs/supers protons + neutrons electronic charge protons how many

  40. Oxidation means losing electrons. We have seen cases where atoms give up electrons to form cations. This is an example of oxidation. Where do such electrons go? Reduction: gaining electrons

  41. Example: chloride anion Consider the case where chlorine gets reduced (gains an electron)  Cl = 1s2 2s2 2p6 3s2 3p5 Cl + e- Cl-

  42. Let’s do another, more highly charged, anion N = 1s2 2s2 2p3 Let it gain three electrons to become nitride:

  43. Suppose we repeat with Mg and F Mg  Mg2+ + 2e- 2e- + 2F  2F- Mg + 2F  MgF2 It takes TWO Fluorines to soak up the TWO electrons from the ONE magnesium. Uh-oh….Here is our first atomic “three-way.”

  44. One oxygen could serve same "soakup" function as 2 fluorides. Mg  Mg2+ + 2e-2e- + O  O2- _____________________________________ Mg + O  MgO Magnesium Oxide

  45. Let’s do Na and N Let’s do Ca and N

  46. Na and N answer 3 Na  3Na+ + 3e-3e- + N  N3- ______________________________________ 3Na + N  Na3N Sodium nitride

  47. Ca and N answer Ca  Ca2+ + 2e-3e- + N  N3- Doesn't balance!Multiply top by 3 and bottom by 2 3 Ca  3Ca+2 + 6e-6e- + 2N  2 N3- ___________________________________________ 3Ca + 2 N  Ca3 N2 Calcium nitride

  48. Here’s a trick for predicting ionic compounds from the periodic table (Life and Chemistry are both full of tricks!) • Count how many electrons the metal must lose to • become like a rare gas. (2 for calcium). • Give this number to the nonmetal. • Count how many electrons the nonmetal must gain to • become like a rare gas. (3 for nitrogen) • Give this number to the metal.

  49. What do Si and O make? What do Al and O make? What do Fe and O make? (uh-oh)

  50. …..can be as simple as adding water NaCl  Na+ + Cl- H2O Sometimes, it is much harder…. e.g., Al2O3 Breaking Ionic Bonds…

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