Chemical bonding

Question

what is the best Lewis structure for CH2Cl2?

Answer 1

First go to a period table and see how many valence electrons each element has:

C= 4 H2= 1 x 2 = 2 Cl2= 7 x 2= 14

Next, determine which atom is the central atom (the element there is only one of). In this case it is Carbon. Carbon would therefore be in the middle.

C

Attach hydrogen by creating bonds to Carbon on either side. Each bond is two valence electrons shared between the atoms.

H---C---H

Since each hydrogen has only one valence electron, we are set there, but carbon only has 2/4 valence electrons it needs. To remedy this, add two more bonds that connect to the Chlorine

Cl

|

H---C---H

|

Cl

Carbon has all valence electrons, but chlorine now only has 2/14. The remaining 12 will go on the other sides of the chlorine, giving you the completed lewis structure:

. .

: Cl :

|

H---C---H

|

: Cl :

^{. .}