Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Lewis Structures and Valence Electrons?

  1. Nov 19, 2008 #1
    Hi there!

    I was wondering if anyone could help me. With Lewis Structures and Valence electrons, do the valence electrons have to go in a certain order around the element symbol?
    ie: four dots around each side of carbon, or two on the left side and two on the right side?

    How would you do one like C₂H₅I?

    One more question, how would one draw a lewis structure for a complex ion, like OH-?

    Thanks! :)
     
  2. jcsd
  3. Nov 20, 2008 #2
    First place each electron one at a time (unpaired) on each of 4 sides of the chemical symbol. Only start pairing them up if you have an atom with more than 4 valence e's.

    Hope this helped.
     
  4. Nov 20, 2008 #3
    No, it doesn't matter what order you have the electrons on the symbol, as long as you have the correct number. Of course, you could have a very anal teacher, in which case, do it how he wants it.

    When drawing OH- what you would do of course, is bond the oxygen and the hydrogen with a single bond (hydrogen can never take more than a single bond) that counts as two of your 8 (it is 8 valence electrons because it is minus, if it was neutral than it would be 7 [6 valence electrons on the oxygen and 1 on the hydrogen]) electrons. Therefore you need to place 6 more electrons, and in this case, the only place to put them is around the oxygen, so you will draw 6 little dots around your O.

    End.
     
  5. Nov 20, 2008 #4
    Thank you very much for your help! I can finish up my report now. :)
    I am understanding these better~!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook