The Lewis dot structure of CHCl3, also known as chloroform, can be drawn by following a series of steps that reflect the molecule’s composition and the valence electrons of its constituent atoms. Chloroform is a compound consisting of one carbon © atom, one hydrogen (H) atom, and three chlorine (Cl) atoms.
To draw the Lewis structure, start with the carbon atom as the central atom since it can form the most bonds (typically four) due to its valence electron configuration and its ability to form stable covalent bonds with other atoms.
Determine the Total Valence Electrons:
- Carbon © has 4 valence electrons.
- Hydrogen (H) has 1 valence electron.
- Each Chlorine (Cl) has 7 valence electrons.
- Total valence electrons = 4 © + 1 (H) + 3*7 (Cl) = 4 + 1 + 21 = 26 valence electrons.
Draw the Skeleton: Place the carbon atom in the center and arrange the hydrogen and chlorine atoms around it. Since carbon forms four bonds and we have one hydrogen and three chlorines, the arrangement will have the hydrogen and three chlorines bonded directly to the carbon.
Connect the Atoms with Single Bonds:
- Connect the carbon to the hydrogen with a single bond (2 electrons).
- Connect the carbon to each chlorine with a single bond (2 electrons each).
- This step uses 2 (for C-H) + 3*2 (for C-Cl) = 2 + 6 = 8 electrons.
Distribute the Remaining Electrons:
- Subtract the electrons used in bonding from the total valence electrons: 26 - 8 = 18 electrons remaining.
- Distribute these remaining electrons as lone pairs around the atoms to satisfy the octet rule for each atom, except for hydrogen which is satisfied with two electrons (its duet).
Satisfy the Octet Rule:
- Carbon already has four bonds (single bonds to H and three Cl atoms), which satisfies its octet.
- Hydrogen has two electrons (from the C-H bond), satisfying its duet.
- Each chlorine needs to complete its octet (eight electrons). With each chlorine having one bond (two electrons) to carbon, we distribute the remaining electrons to fulfill the octet for each chlorine. Since there are 18 electrons left and 6 are used in bonds to chlorines, 12 electrons remain for the chlorines as lone pairs, which gives each chlorine 6 electrons (3 lone pairs) in addition to the 2 electrons in the bond to carbon, thus fulfilling the octet for each chlorine.
The final Lewis dot structure for CHCl3 has the carbon bonded to one hydrogen and three chlorines, with three lone pairs on each chlorine and a single bond between carbon and each of the other atoms. This structure illustrates the molecule’s covalent bonds and lone pairs, showing how the valence electrons are distributed to achieve stability according to the octet rule for the non-hydrogen atoms.
This molecular structure is crucial for understanding the chemical and physical properties of chloroform, including its reactivity and molecular polarity, which in turn influences its interactions with other molecules and its utility in various applications, from solvents to pharmaceuticals.
