This is the C2H2Cl2 Lewis structure.
Carbon has 4 valence electrons, two Carbons;
Hydrogen has 1 valence electron, but we have
two Hydrogens; plus Chlorine, which is 7,
and we have two Chlorines, for a total of
24 valence electrons.
Carbon's the least electronegative, and we'll
put that in the center, and we know Hydrogens
always go on the outside.
But here's the problem: where do we put the
Hydrogens?
Do we do it like this, where we put two Hydrogens
on on side and two Chlorines on the other?
Or do we do it like this, where we have a
Hydrogen and Chlorine on one side, and then
on the other we have a Hydrogen and Chlorine.
They're very different chemical compounds.
They have different properties.
So we can't really tell, looking at this structure
up here, which way we're supposed to do it.
So let's go with this right now.
We have 24 valence electrons for the C2H2Cl2
Lewis structure.
We'll put two electrons between atoms to form
the chemical bonds, like this, so I've used
10.
Then around the Chlorines, 12, 22, and then
back to the central Carbons, 24.
But we've used all 24 valence electrons.
We can see that both Hydrogens have 2 valence
electrons, and that's all they need for a
full outer shell.
This Carbon here has 8, the Chlorine, and
this Chlorine has 8 as well.
Their octets are completed.
However, this Carbon right here only has 6.
So we're gonna have to share electrons to
form a double bond in order to get it to 8
valence electrons.
Let's move these 2 valence electrons right
here into the center to form a double bond.
We're still using 24 valence electrons, but
now this Carbon here has 8 valence electrons,
as does this.
So the octets are complete on all the atoms
in the C2H2Cl2 Lewis structure.
For this structure, because we have the Chlorines
on the first and second Carbons, we're going
to call it 1, 2-Dichloroethene.
If both Chlorines were on the first Carbon,
it would be 1, 1-Dichloroethene.
That's the Lewis structure for C2H2Cl2.
This is Dr. B., and thanks for watching.
