The Lewis structure for CH2Cl2 (dichloromethane) can be drawn by following these steps:
- Count the total number of valence electrons: Carbon has 4, each hydrogen has 1, and each chlorine has 7. So, 4 + (2 × 1) + (2 × 7) = 20 valence electrons.
- Place the carbon atom in the center and arrange the hydrogen and chlorine atoms around it.
- Draw single bonds between the carbon atom and each of the surrounding atoms. This uses 8 electrons (4 bonds × 2 electrons).
- Distribute the remaining 12 electrons as lone pairs on the chlorine atoms, giving each chlorine 3 lone pairs.
The molecular geometry of CH2Cl2 is tetrahedral. This is because the central carbon atom is bonded to four other atoms (two hydrogens and two chlorines), and there are no lone pairs on the carbon atom.
CH2Cl2 is a polar molecule. The difference in electronegativity between carbon and chlorine creates a dipole moment. Since the molecule is not symmetrical (the dipoles do not cancel out), it is polar.