Lewis structure of CH
Cl
Construct the Lewis structure model for the covalent compound carbon tetrachloride (CCl
) using the following steps. (1) The total number of valence electrons in CCl
is __. (2) Write the atomic core for the element that seems most likely to be the central atom in the molecule in the space below. Position the remaining atomic cores around it. (3) Place an electron pair between each of the bonding atoms. (4) After distributing the remaining valence electrons so that the carbon and each chlorine atom has an electron octet, write the Lewis structure for CCl
in the box. Lewis structure of CCl
The Correct Answer and Explanation is:
Correct Answer:
(1) The total number of valence electrons in CCl₄ is 32.
(2) The central atom is carbon (C).
(3) Each chlorine (Cl) is bonded to the central carbon atom using a pair of shared electrons.
(4) The Lewis structure of carbon tetrachloride (CCl₄) is:
markdownCopyEdit Cl
|
Cl — C — Cl
|
Cl
Each bond (C—Cl) represents two shared electrons. Each chlorine also has six non-bonding electrons (three lone pairs), and carbon is surrounded by four shared pairs, completing its octet.
Explanation
To draw the Lewis structure of carbon tetrachloride (CCl₄), we follow systematic steps.
Step 1: Count total valence electrons.
Carbon (C) has 4 valence electrons, and each chlorine (Cl) has 7 valence electrons. Since there are four chlorine atoms:
- Carbon: 1 × 4 = 4 electrons
- Chlorine: 4 × 7 = 28 electrons
- Total = 4 + 28 = 32 valence electrons
Step 2: Choose the central atom.
The central atom is usually the least electronegative element that is not hydrogen. Carbon is less electronegative than chlorine, so carbon goes at the center. The four chlorine atoms are placed around it.
Step 3: Place a bonding pair (2 electrons) between carbon and each chlorine atom.
Each of these four single bonds accounts for 8 electrons (4 bonds × 2 electrons).
Step 4: Distribute remaining electrons to satisfy the octet rule.
We have used 8 electrons in bonds. That leaves 32 – 8 = 24 electrons. These are distributed as lone pairs on the chlorine atoms (6 electrons on each Cl atom, since each already has 2 electrons from the bond with carbon).
Each Cl atom ends up with 8 electrons total (2 bonding + 6 lone pair electrons), and carbon is surrounded by 8 bonding electrons (4 single bonds), which also fulfills its octet.
The structure is symmetrical, and each atom achieves a full octet. CCl₄ is a nonpolar molecule due to its symmetrical shape, even though the individual C–Cl bonds are polar.
