Chem 112

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Chem 112
2010-09-23 15:35:38
Valence Bonds 1st chem test

Valence Bonds & Electrons
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  1. What is the valence bond theory?
    Only half-filled orbitals that constructively interfere can make bonds
  2. What is amplitude?
    How high the wave is from zero
  3. What is the frequency of a wave?
    The cycles per second
  4. Do waves move at different speeds?
    No, they all move at the speed of light
  5. Wavelength & Frequency have a(n) _______ relationship.
    • An inverse relationship
    • Smaller wavelength = greater freq. = high energy
  6. What is the wave particle duality?
    Light acts as particles
  7. Give the definition for constructive interference of waves.
    Adding together waves that move in the same direction. The wave will still have the same energy because frequency stays the same
  8. Give the definition of destructive interference.
    When two different waves destroy each other or cancel each other out (positive & negative amplitude come together)
  9. When e- release energy coming back down to ground state, what is the energy (light) released as?
    A photon
  10. How many e- can an orbital hold?
  11. How many shapes does the 's' level have?
  12. How many shapes does the 'p' level have?
    3 - px, py, pz
  13. How many shapes does the 'd' level have?
    5 - dxy, dyz, dxz, dz^2, dx^2-y^2
  14. What is the Aufbau Principle?
    The lowest energy orbitals are filled 1st
  15. What is the Pauli Exclusion Principle?
    Only 2 e- per orbital
  16. What is Hund's Rule?
    If equal energy orbitals are available, then 1 e- per orbital & then start doubling up
  17. What is the outer e- configuration?
    What's written to the right. Of the noble gas shortcut (everything)
  18. What is the valence e- configuration?
    • The outermost e- in the outermost shell
    • E.G. Se: [Ar] 4s2 3d10 4p4
    • Valence: 4s2 4p4
  19. What elements are the exceptions for the orbital diagrams/electron configurations?
    • 4th & 9th column of transition metals of the 1st two rows
    • Rules: Mo: [Kr] 5s2 4d4
    • Act.: Mo: [Kr] 5s1 4d5
  20. Why do exceptions exist in writing/drawing orbitals?
    To complete stability. Needs a full subshell or a half filled one
  21. Where will transition metals lose e- from 1st?
    From the 's' orbital
  22. What are the two types of bonds?
    Sigma & Pi
  23. Why do we hybridize molecules?
    To get the correct geometry
  24. What is a Pi bond?
    A double bond
  25. What is a Sigma bond?
    All bonds (single & double)
  26. A central atom that has a 'sp' hybridization has a(n) _________ geometry.
    Linear (with 2 unhybridized 'p' bonds) 180*
  27. A central atom that has a 'sp2' hybridization has a(n) __________ geometry.
    Trigonal Planar (with 1 unhybridized 'p' bond) 120*
  28. A central atom that has a 'sp3' hybridization has a(n) ________ geometry.
    Tetrahedral (with 0 unhybridized 'p' bonds) 109.5*
  29. A central atom that has a 'sp3d' hybridization has a(n) ___________ geometry.
    Trigonal Bipyramidal (with 0 unhybridized 'p' bonds) 90*, 120*, 180*
  30. A central atom that has a 'sp3d2' hybridization has a(n) ____________ geometry.
    Octahedral (with 0 unhybridized 'p' bonds) 90*
  31. The hybridization scheme depends on the number of _____ the molecule makes
  32. If the central atom has a 4 bonds, what would the hybridization scheme be?
  33. In hybridization, each orbital (s,p, etc) accounts for how many bonds?
    1 bond each. If the central atom has a hybridization scheme of sp3d, there would be 5 bonds formed.
  34. True or false: Electrons are between the nuclei in a sigma bond but there is no electron density directly between the nuclei in a pi bond.
  35. Electrons were proven to have a wave nature when __________.
    A beam of e- made an interference pattern when passed through a double slit