Imagine you are to build the Lewis structure for a compound CCI,Br2. Which element will be the element in the structure ?
CI
Br
C
either Cl or Br
The Correct Answer and Explanation is :
In the compound CCI₃Br₂ (which likely refers to trichlorobromomethane), the central element in the Lewis structure will be Carbon (C). Here’s why:
- Carbon’s Role as the Central Atom: In most covalent compounds, the least electronegative atom tends to be the central atom. Carbon, with an electronegativity of around 2.55, is less electronegative than both chlorine (Cl) and bromine (Br), which have electronegativities of 3.16 and 2.96, respectively. Therefore, carbon will be the atom at the center of the molecule, surrounded by the halogens (Cl and Br).
- Bonding in CCI₃Br₂: The Lewis structure of CCI₃Br₂ will have carbon bonded to three chlorine (Cl) atoms and two bromine (Br) atoms. Carbon typically forms four bonds, which is its typical valence, and since each chlorine and bromine will form a single bond with carbon, this satisfies carbon’s bonding requirements.
- Electron Distribution: Chlorine and bromine are both halogens, which means they need one electron to complete their octet, and they will form single bonds with carbon. Chlorine, being more electronegative than bromine, will tend to pull electron density away from the carbon atom, but since carbon has a lower electronegativity, it will still serve as the central atom.
- Molecular Geometry: The structure will be a roughly tetrahedral geometry around the carbon atom, with the three chlorine atoms and two bromine atoms arranged in the most stable configuration around carbon.
In conclusion, carbon (C) will be the central atom in the Lewis structure for CCI₃Br₂ because it is the least electronegative element and can form the necessary number of bonds to satisfy its valency.