[annalevy]

AHHHHHHHHH my chemistry teacher doesn't teach!
How do I make a Lewis Structure out of IBr, CH₃BR , C₂HCI, SiCI₄ , and F<sub>2[/subO ?

Please *delete me*

--confused chemistry student</sub>

[DevaDevil]

Start with counting the valence electrons in each atom.
See if there is a logical choice for a central atom (where more atoms will be bonded to; like Carbon which has 4 valence electrons, hence will try to form 4 bonds, or Nitrogen which has 5 valence electrons, thus tries to form 3 bonds)
Then pair them up in bonds to have every atom surrounded by 8 electrons (a bond is 2 shared electrons, they count towards the 8 for both atoms in the bond)

I give the example of IBr:
Each has 7 valence electrons; they will try to make 8 each, thus will form 1 bond. The other 6 electrons per atom (the ones not needed for the bond) will be drawn as unbound electron pairs around the atoms.
Each atom now has 8 electrons surrounding it: 6 from the unbound pairs and 2 from the bond.

[constant thinker]

Google is helpful.

http://antoine.frostburg.edu/chem/senese/101/bonds/faq/simple-lewis-structures.shtml

http://www.google.com/search?hl=en&q=Lewis+Structure&btnG=Google+Search