Ch 2 Notes

Card Set Information

Ch 2 Notes
2013-09-14 08:48:09
CHM 201

Show Answers:

  1. What are orbitals?
    mathematical probabilities of finding electrons in space
  2. S orbitals are __. P orbitals are __.
    • spheres
    • dumbbell
  3. The further away from the nucleus that you go, what?
    Explain mass of atoms. 
    Explain what electrons do.
    • the less likely you are to find an electron
    • the mass of atoms is confined to the nucleus
    • find each other first
  4. If we take two s orbitals and combine them, what do we get?
    a bonding MO
  5. What does plus and minus pertain to?
    • the orbitals
    • plus is bonding
    • minus is antibonding
  6. What is between two nuclei?
    positive electron density
  7. When you combine two atomic orbitals, you get __. Explain that.
    • two bonding orbitals
    • one used, one not
    • one bonding, the other anti
  8. Which has higher energy, bonding or antibonding?
  9. Orbitals house how many electrons.
  10. Single bond equals ___.
    A double bond equals ___.
    • sigma
    • sigma and pi
  11. The closer the atoms get to each other, the __. When they reach a __, they achieve a __.
  12. If you supply enough energy, you can do what?
    move electrons or promote to antibonding
  13. Even though you expend energy raising electrons, what?
    you get it back by forming bonds
  14. What do all p orbitals have? What will one do?
    • a + and - lobe with a node in the middle. 
    • the + will expand at the expense of the -
  15. Rotation occurs in what? What is it called?
    • in single bonds
    • particular conformations
  16. Sigma bonds are __
    head on overlap of two hybrid orbitals
  17. Pi bonds are made up of __. 
    They must be __ to each other.
    They are __
    • exposed; a top part and a bottom part
    • parallel
    • not twice as strong as single bonds; they are considerably weaker
  18. No __ around a double bond.
    free roation
  19. If you rotate a double bond, what do you do?
    you break the double bond and hcange the properties
  20. What's left after sigma bonds are __.
    pi bonds left over
  21. True or False: 
    saturated atoms in a ring are flat
    • false
    • not flat
  22. wedges indicate __
    the structure is coming at you
  23. dashes indicate
    the structure is going away from us
  24. The farther away from the nucleus you get, what?
    the lower the electron density
  25. Destructive overlap of waves causes __.
    • antibonding MO
    • opposite waves separated by a function
  26. __ lies between the nuclei. 
    A bond may be formed by __ 
    The __ is lower in energy than the original atomic orbitals
    The __ is higher in energy than the atomic orbitals
    • electron density
    • s-s, s-p, p-p
    • bonding MO
    • antibonding MO
  27. P orbitals occupy the __.
    Cartesian coordinates
  28. P orbitals are __ from each other, but we don't use that angle. WE only use __.
    • 90
    • 120
    • 109
    • 180
  29. The excited state does what?
    bump electrons to higher energy orbitals
  30. Ethane is composed of __ bonded by the overlap of their __. 
    There is __ along single bonds.
    • two methyl groups
    • sp3 hybrid orbital
    • free rotation
  31. A double bond (two pairs of shared electrons) consists of __>
    a sigma bond and a pi bond
  32. A __ (three pairs of shared electrons) consists of __.
    • triple bond
    • sigma bond
    • two pi bonds
  33. True or False:
    Double bonds cannot rotate. 
    Explain whether true or false.
    • True
    • it'll break the pi bond
  34. Compounds that differ in how their substitutents are arranged around the double bond can be __ and __.
    • isolated
    • separated
  35. Isomerism:
    - What are they?
    molecules that have the same molecular formula but differ in the arrangement of their atoms are called isomers
  36. Constitutional isomers
    differ in their bonding sequence
  37. Stereoisomers
    differ only in the arrangement of the atoms in space
  38. Constitutional isomers have the __, but the atoms are __. 
    They have __.
    The number of isomers increases rapidly as the __ increases.
    • same chemical formula
    • connected in a different order
    • different properties
    • number of carbon atoms
  39. Stereoisomers
    are compounds with the atoms bonded in the same order, but their atoms have different orientations in space
  40. __ are examples of geometric stereoisomers; they occur when there is a __ in the compound.
    • cis and trans
    • double bond
  41. Since there is no free rotation along the __, the groups on these carbons can __.
    • carbon carbon double bond
    • point to different places in space
  42. The best bonding orbitals are those that __.
    provide the greatest electron density in the bonding region while keeping the three pairs of bonding electrons as far apart as possible
  43. Bond angles cant be explained with simple __. 
    __ is used to explain the molecular shape of molecules.
    __ are lower in energy because __ are farther apart.
    • s and p orbitals
    • valence-shell electron pair repulsion theory (VSEPR)
    • hybridized orbitals
    • electron pairs