Answer
Lewis structure for CHCl3:
Electrons pairs = 13 electrons pairs.
The molecular geometry of CHCl3 is tetrahedral.
Explanation
Lewis Structure for CHCl3:
There are some steps or guidelines to follow when drawing a Lewis structure for CHCl3. The steps include but are not limited to the following:
1. Find the total number of electrons of the valance shells of carbon, hydrogen, and chlorine atoms.
2. Determine total electrons pairs existing as lone pairs and bonds.
3. Deciding center atom selection.
4. Mark lone pairs on atoms.
5. Mark charges on atoms if there are charges.
6. Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain the best Lewis structure.
Using a ChemDraw tool, the Lewis structure for chloroform, CH3Cl3 is shown below:
Electron pairs:
There are three elements in chloroform; carbon, hydrogen, and chlorine. Hydrogen is a Group IA element in the periodic table and only has one electron in its valence shell. Carbon is a Group IVA element in the periodic table and has four electrons in its valence shell. Also, Chlorine is a group VIIA element in the periodic table and contains seven electrons in its last shell.
Therefore,
valence electrons given by hydrogen atom = 1 x 1 = 1
valence electrons given by carbon atom = 4 x 1 = 4
valence electrons given by chlorine atoms = 7 x 3 = 21
Total valence electrons = 1 + 4 + 21 = 26.
Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells
Total electron pairs are determined by dividing the number of total valence electrons by two.
For, CHCl3, the total pairs of electrons = 26/2 = 13 electron pairs.
Molecular geometry:
Hybridization of CHCl3 is sp³, with a bond angle of 109.5º. Hence, the molecular geometry of CHCl3 is tetrahedral.
