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I tried

  1. Jan 14, 2004 #1
    sorry but this si really hard for me i don't understand these 2 question.

    Explain why some noble gases such as Xe will form compounds and some such as Ne will not?


    What kinds of orbital arrangemenets contribute to the bonding in ethene

    H2C = CH2

    thats a double bond

    i tried and i don't understand.
     
  2. jcsd
  3. Jan 14, 2004 #2
    trigonal planar

    All atoms will be on a flat plane with the Hydrogens coming off at a 120 angle.

    Nautica
     
  4. Jan 15, 2004 #3
    Xenon has a much lower ionization energy than neon, by a difference of a 1000 or so kJ/mol. In other words it will take less energy to strip an electron off xenon and make it reactive compared to neon. It still takes a lot of energy though.

    In ethene, the carbons are sp2 hybridized.
    /:up spin
    \:down spin

    CH2=CH2
    2s _/\_
    2p _/_ _/_ __

    make
    sp2 _/\_ _/_ _/_
    and the leftover 2p __
    with two spots for the two hydrogens and an empty 2p orbital that overlaps with the adjacent carbons empty 2p to make the pi bond. I hope that wasn't too confusing. Do you have a textbook that you use with your class?
     
    Last edited: Jan 15, 2004
  5. Jan 15, 2004 #4
    I'm pretty sure they've formed compounds with neon. In fact I think that was the first noble gas they've got to form compounds.
     
  6. Jan 15, 2004 #5

    Bystander

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    Uh, nope --- Xe first, then Kr. I s'pose radon's the most reactive of the group, but the 4 day half-life takes all the fun out of playing with it.
     
  7. Jan 15, 2004 #6

    GCT

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    Elements farther down the column have higher quantum numbers and as a result the valence electrons have less effective nuclear charge; thus low ionization energy and most importantly of all they are able to be polarized. An example of this is their ability to more easily form van der wal bonds. Simply said, Xe's electrons are more "available" due to its outer location as well as its polarization characteristics.
    Remember though that these compounds are most likely induced-ionic or induced dipole bonds. The stability of nobles gases and thus their instabilty as compounds can be explained through molecular orbital theory.

    Hybridized SP2 atomic orbitals form sigma molecular orbitals with SP2 and S orbitals, overlapping Pz orbitals forms the pi shaped molecular orbital.

    Hope this helps.
     
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