For the CH4O Lewis structure, we have 14 valence
electrons.
So there are a number of ways to draw the
Lewis structure for CH4O in which each of
the atoms has a full outer shell and we only
use 14 valence electrons.
So I've drawn three here.
When I look at these structures, my experience
tells me that it's sort of odd to see a lone
pair of electrons on those Carbon atoms.
The Oxygen, I'm more used to seeing, but I
don't see them so often on Carbon.
So that makes me think that this structure
may be the best Lewis structure.
However, what I can do is calculate formal
charges for each of the atoms to get more
information about what might be the best Lewis
structure.
When I calculate the formal charges, this
is what I find.
Now, in the structure at the top, we have
a negative for Carbon, and a plus two for
Oxygen.
Now I know Oxygen is more electronegative
than Carbon, so this doesn't make sense to
me.
And I want my formal charges to be as close
to zero as possible, so that structure doesn't
make sense.
The structure on the bottom's a little closer:
the negative's on the Oxygen, the positive's
on the Carbon; but still, I'd like my formal
charges to be as close to zero as possible.
The structure on the left is the one that
really achieves that and really is the most
appropriate Lewis structure for CH4O.
So that's the Lewis structure for CH4O.
This is Dr. B., and thanks for watching.
