Could someone please give me the Lewis Diagram for Diazepam , otherwise known as Valium. The formula is C16 H13 Cl N2 O... Thanks A lot!

This is a very unusual request and I'm not exactly sure how to answer your question. Lewis structures aren't very predictive so they aren't commonly used by practicing chemists. Also, I can't really draw it here so I'll describe it and let you draw it.

You can see the structure of Diazepam here:

Diazepam - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Diazepam)

Diazepam has a seven-member ring containing two nitrogen atoms. One of the nitrogen atoms has a double-bond in it and the other is bonded to two carbons and one hydrogen. Each single bond is one pair of electrons; each double bond is two shared pairs of electrons. The C=N-C nitrogen has an unshared pair of electrons as does the C-NH-C nitrogen. The chlorine has three unshared pairs of electrons. The oxygen is connected via a double-bond to the nearby cargon atom. The double bond is two shared pairs of electrons. The oxygen has two unshared pairs of electrons.

There are two 6-membered conjugated rings (benzene rings) in the structure. Each carbon atom in the ring shares one pair of electrons with the attached hydrogen atom and one pair of electrons with each adjacent carbon atom. The remaining pair of electrons is shared with both adjacent carbon atoms. I'm not sure how you'd draw that in a lewis structure. All other carbon atoms have four pairs of electrons that are shared as the bonds indicate -- one per bond.

Where the structure shows only three bonds to a carbon atom, there is an implicit bond to a hydrogen atom that is not shown.