1. Guest, be sure to check out How To Get Into Dental School, our free downloadable PDF with step-by-step details for dental school applicants!
    Dismiss Notice
  2. Dismiss Notice

Gen Chem Q

Discussion in 'DAT Discussions' started by topdent1, Jun 6, 2008.

  1. topdent1

    Joined:
    Aug 6, 2007
    Messages:
    553
    Likes Received:
    4
    Status:
    Pre-Dental
    If 2 atoms are bonded together, one with six valence electrons, the other with 4, how many electrons must they share for both to achieve a full octet?

    The answer is 6 but I don't know why.
     
  2. Thread continues after this sponsor message. SDN Members do not see this ad.

  3. Mstoothlady2012

    Joined:
    Apr 7, 2007
    Messages:
    1,714
    Likes Received:
    4
    Status:
    Dental Student
    Total electrons --> 6+4 =10
    Now you have to combine them in such a way that each atom fulfills the octet rule. In order to do that both atoms will have to form 3 covalent bonds (6 electrons) between them. Remaining 4 will be divided among two atoms; 2 for each. Hence now each atom has 8 electrons; 1 lone pair; and 6 shared electrons.
     
  4. DDSguyLA

    Joined:
    Mar 12, 2008
    Messages:
    386
    Likes Received:
    0
    Status:
    Pre-Dental
    WELL said.
    Add the total Valence electrons. Start with the bonds give as much then try to obey octet rule on each atom... a little mix and match will do the job.
     
  5. smile101

    Joined:
    Dec 4, 2007
    Messages:
    401
    Likes Received:
    0
    Status:
    Pre-Dental
    A more systematic way I learned in my gchm class is here:

    Suppose the two elements are X and Y

    Total valence e: 10
    so put X-Y
    Now, # available: 8 (bc you used 2 to form a single bond between the two)
    # required to fill the octet: 12 (6/ element)
    This means that you need 4 extra electrons than available (12-8=4), so put 2 extra bonds, which results in a triple bond between X and Y.
    These are all the bonds you will have, and you will put one extra pair of electrons on each one to use all the 10 electrons.

    Wish I had paper and pen to explain this, but oh well.
    Hope this helps!!
     

Share This Page