How to Draw the Lewis Dot Structure for C2Cl4 (Tetrachloroethylene)?

To draw the Lewis dot structure for tetrachloroethylene (C2Cl4), we need to follow a series of steps:

1. Count the total number of valence electrons: Carbon (C) has 4 valence electrons, and Chlorine (Cl) has 7 valence electrons. For C2Cl4, we have:
   • 2 C atoms: 2 x 4 = 8 electrons
   • 4 Cl atoms: 4 x 7 = 28 electrons

   Adding these gives us a total of 8 + 28 = 36 valence electrons.

2. Arrange the atoms: The two carbon atoms will be the central atoms because they bond with each other and are surrounded by chlorine atoms. The structure will look like this:
   
   Cl – C – C – Cl
   
        |     |
   
        Cl      Cl
3. Distribute the electrons: Start by forming single bonds between the carbon atoms and the chlorine atoms. Each single bond uses 2 electrons. So we will use 4 bonds (2 between each C and Cl) which accounts for 8 electrons:
   
   Cl: 1 pair
   
   C – C
   
   Cl: 1 pair
   
        |    
   
        Cl      Cl
4. Complete the octets: Each chlorine atom needs 8 electrons to satisfy the octet rule. The chlorine atoms will hold 3 lone pairs each:
   
   Cl: 3 pairs
   
   C – C
   
   Cl: 3 pairs
   
        |    
   
        Cl      Cl
   
   Each carbon is bonded to two chlorines and has 2 shared electrons from the bond with the other carbon atom, totaling 8 electrons, thus satisfying the octet rule for carbon as well.

In summary, the final Lewis structure of tetrachloroethylene (C2Cl4) looks like this:

   Cl    Cl
    |    |
Cl - C = C - Cl

This structure shows that both carbon atoms are double-bonded to each other and single-bonded to two chlorine atoms, with all atoms achieving their full valence requirement.