Cucolio Draw the best Lewis structure for CCl3. What is the formal charge on the C?
The Correct Answer and Explanation is:
C = 4 – 2 – (1/2 × 6) = 4 – 2 – 3 = -1
This result is consistent, as the sum of formal charges ( -1 for carbon and 0 for eachThe formal charge on the C atom in CCl₃⁻ is -1.
To determine this, we first need to construct the best Lewis structure for the trichloromethanide anion, CCl₃⁻. The process begins by calculating the total number of valence electrons available for bonding. Carbon, being in Group 14 of the periodic table, contributes 4 valence electrons. Chlorine, in Group 17, contributes 7 valence electrons, and with three chlorine atoms, this totals 21 electrons. The negative one charge of the anion indicates the presence of an additional electron. Therefore, the total number of valence electrons to be distributed in the structure is 4 + 21 + 1 = 26.
Next, we identify the central atom for chlorine) equals the overall charge of the ion. the structure. Carbon is less electronegative than chlorine, so it is placed in the center, forming single bonds with the three surrounding chlorine atoms. This skeletal structure uses 6 electrons (3 bonds × 2 electrons/bond).
The remaining 20 electrons (26 – 6) are then distributed as lone pairs. We start by completing the octets of the terminal atoms, which are the chlorines. Each chlorine atom already has two electrons from its bond with carbon and requires six more to complete its octet. We add three lone pairs (6 electrons) to each of the three chlorine atoms,
