bravomedic - 25-9-2006 at 17:53
You are given the molecular formula SO(Cl)2 and are told to draw the Lewis dot structure of this molecule. In
the problem it states that S is the central atom, but I was just wondering, without being told this is there anyway that you would know that? Would
you otherwise choose S because it is less electronegative than O?
Thanks in advance!
Blind Angel - 25-9-2006 at 21:06
Yup, electronegativity it is, and also you could note that S can have oxidation number -2, 0 and +4, oxygen can be only -2 and in peroxide, when you
have X2O2, it's -1 (maybe other one in very specific case), Cl can be -1, +1, +3, +5, +7, in most case you should consider it as
-1. So since it's basic chemistry let's consider Cl as -1 and O as -2, the only one that can change is S. By easy calculation you can make 2x-1 + 1x-2
which is -4, you need to make the molecule neutral since it has no charge (like in NO3-). Happily sulfur can be +4 so oxygen can hook on to
it, and Cl too, thus making it the central one. Hope I'm clear.
After having written all this, I notice that I can find any exemple where the electronegativity trick doesn't work, so you're probably better to stick
to it (simpler). But eventually you'll learn using oxidation number, maybe what I just wrote will help you then.