Draw the Lewis Structure for C2H4Cl2 and State its Molecular Geometry: Is it Polar or Nonpolar?

To draw the Lewis structure for C₂H₄Cl₂, we begin by counting the total number of valence electrons. Carbon (C) has 4 valence electrons, hydrogen (H) has 1, and chlorine (Cl) has 7. Therefore, the total is:

• 2 Carbons: 2 x 4 = 8
• 4 Hydrogens: 4 x 1 = 4
• 2 Chlorines: 2 x 7 = 14
• Total: 8 + 4 + 14 = 26 valence electrons

Next, we place the carbon atoms in the center, as they are less electronegative. The general structure is:

C - C

Now, we connect the carbon atoms with a single bond and attach the four hydrogen atoms and two chlorine atoms. The structure will look like this:

   H   Cl
    |   |
H - C - C - H
    |   |
   H   Cl

Now that we have the skeletal structure, we need to confirm that all atoms have a complete octet (except hydrogen, which only needs 2 electrons). In this structure, each carbon has 4 bonds (2 with hydrogen and 2 with chlorine) and each chlorine has 1 bond and 6 lone pairs, which satisfies the octet rule.

To determine the molecular geometry, we look for regions of electron density around the central atoms (the two carbon atoms). Each carbon atom has 4 bonding pairs (single bonds). This arrangement leads to a tetrahedral electron geometry around each carbon, but since we do not have lone pairs on the carbon atoms, the molecular geometry is actually planar.

Next, we need to assess the polarity of the molecule. Despite the symmetrical arrangement of the hydrogen and chlorine atoms around the carbon chain, the presence of the chlorine atoms makes the molecule polar. Chlorine is more electronegative than carbon and hydrogen, resulting in a dipole moment. The overall shape of the molecule causes these dipoles not to cancel out completely, resulting in a net dipole moment.

In conclusion, the Lewis structure for C₂H₄Cl₂ is represented correctly with a planar structure, and it is considered polar due to the unequal sharing of electrons between chlorine and hydrogen atoms.