The Lewis structure for CHCl3 (chloroform) can be drawn by following these steps:
- Count the total number of valence electrons:
- Carbon (C) has 4 valence electrons.
- Hydrogen (H) has 1 valence electron.
- Chlorine (Cl) has 7 valence electrons, and there are 3 chlorine atoms, so 7 x 3 = 21 valence electrons.
Total valence electrons = 4 (C) + 1 (H) + 21 (Cl) = 26 valence electrons.
- Determine the central atom:
Carbon (C) is the central atom because it is less electronegative than chlorine (Cl).
- Draw the skeletal structure:
Place the carbon atom in the center and connect it to the hydrogen atom and the three chlorine atoms using single bonds.
- Distribute the remaining electrons:
After forming the single bonds, you have used 8 electrons (2 for each bond). Subtract this from the total valence electrons: 26 – 8 = 18 electrons.
Distribute these remaining electrons as lone pairs on the chlorine atoms. Each chlorine atom will have 3 lone pairs (6 electrons).
- Check the octet rule:
Ensure that all atoms (except hydrogen) have a complete octet. Carbon has 4 bonds (8 electrons), and each chlorine has 3 lone pairs and 1 bond (8 electrons).
The final Lewis structure for CHCl3 looks like this:
Cl
|
Cl—C—H
|
Cl
This structure shows the arrangement of atoms and the distribution of electrons in chloroform.