Draw the best lewis structure for CCl3 +1. What is the formal charge on the C?
The Correct Answer and Explanation is :
The molecular ion CCl₃⁺ consists of a carbon atom (C) bonded to three chlorine atoms (Cl). It carries a positive charge, meaning it has one less electron than a neutral molecule would have.
Step-by-Step Approach to Drawing the Best Lewis Structure:
- Determine the total number of valence electrons:
- Carbon (C) has 4 valence electrons (group 14 element).
- Chlorine (Cl) has 7 valence electrons (group 17 element), and there are three chlorines.
- Since this is a CCl₃⁺ ion, we subtract 1 electron due to the positive charge. So, the total number of valence electrons is:
[
4 + (3 \times 7) – 1 = 4 + 21 – 1 = 24 \text{ electrons}
]
- Arrange the atoms:
Carbon (C) will be the central atom because it is less electronegative than chlorine (Cl). - Place single bonds:
Draw single bonds between the carbon and each chlorine atom. Each single bond consists of 2 electrons, so 6 electrons are used (3 bonds × 2 electrons). - Distribute remaining electrons:
After placing the bonds, 18 electrons remain. These will be placed as lone pairs on the chlorine atoms to complete their octet. Each chlorine will get 3 lone pairs (6 electrons per chlorine), filling their octets. - Account for the positive charge:
The positive charge means that carbon has lost an electron. This can be reflected by reducing the number of electrons on carbon. This means carbon will only have 6 electrons in its valence shell after bonding (2 from each bond with chlorine), which results in a formal charge of +1 on the carbon atom.
Formal Charge Calculation on Carbon:
The formal charge formula is:
[
\text{Formal charge} = \text{Valence electrons of C} – \text{Nonbonding electrons} – \frac{\text{Bonding electrons}}{2}
]
For C:
- Valence electrons = 4
- Nonbonding electrons = 0
- Bonding electrons = 6 (from the 3 C-Cl bonds)
So:
[
\text{Formal charge} = 4 – 0 – \frac{6}{2} = 4 – 3 = +1
]
Thus, the formal charge on the carbon atom is +1.
The Best Lewis Structure:
- The carbon is in the center with three single bonds to the chlorine atoms, and each chlorine has three lone pairs of electrons.
- The formal charge on the carbon is +1, and the chlorines have no formal charge.
I’ll generate the image of this structure for you.
Here is the Lewis structure for the CCl₃⁺ ion. The carbon atom is at the center with three chlorine atoms bonded to it. Each chlorine atom has three lone pairs, and the carbon atom carries a formal charge of +1.
Let me know if you’d like further details or modifications!
