Xe would be your central atom, O is attached to it by a double bond and your two Fs are attached be a single bond.
There would be 3 Lone Pair (LP) electrons around F, 2 around O, and 2 around Xe. Why ? There is no valance to this molecule so you want to satisfy the formal charge to be 0. Formal charge = (#electrons in ground state) - [ (free electrons) - 1/2 (bonding electrons)].
Formal charge for F, would want 0 so
0 = 7 - [? + 1/2 (2) ] = 7 - (? +1) = 7 - ? - 1
? = 6, therefore 3 lone pairs around fluorines.
Formal charge for O, would want 0 so
0 = 6 - [? + 1/2 (4) ]...
? = 4, therefore 2 LP around oxygen
Formal charge for Xe, again we want it to be 0 so,
0 = 8 - [? + 1/2 (8)].....
? = 4, therefore 2 LP around Xe.
Kind of a weird set up (since Xe does not follow the octect rule), but it works out =)
Xe does not follow the octet rule because it has access to the 4d sublevel. Xe is the central atom, single bonded to 4 F atoms. The Xe also has 2 lone pairs.
H-O-Cl
h-s=s-h
I l As -I l I As has 3 valence electrons and I has 1
CaCO3 does not have a lewis structure because this molecule is composed of ions. (Ca+2 and CO3-2). you have to draw the lewis structure of the ions separately, as shown in the parenthesis.
It is a lewis base because of its lone pair of electrons that can be "donated". If you draw/look at the lewis structure it is much easier to tell. Especially when the formula is not that of an ion!
c4h10o
H-O-Cl
dots
h-s=s-h
I uploaded a jpg of the acetate ion Lewis structure to imageshack. Just click the "related link" below and you should see it. Many people draw Lewis Structures with minor variations, but this should give you the basic idea.
Draw the Lewis Structure
Will this link help you?, it is quite impossible to draw a Lewis dot structure in this simple text editor. See related links.
See this question for how to draw the Lewis Dot structure of any molecule:[http://wiki.answers.com/Q/How_do_you_draw_Lewis_dot_structuresHow do you draw Lewis dot structures?]
CaCO3 does not have a lewis structure because this molecule is composed of ions. (Ca+2 and CO3-2). you have to draw the lewis structure of the ions separately, as shown in the parenthesis.
I l As -I l I As has 3 valence electrons and I has 1
Lewis structure for cobalt chlorit
It is a lewis base because of its lone pair of electrons that can be "donated". If you draw/look at the lewis structure it is much easier to tell. Especially when the formula is not that of an ion!