Draw the Lewis structure of Cl2O, add non-zero formal charges to atoms. The Cl must be the central atom
The Correct Answer and Explanation is:
Lewis Structure of Cl₂O (with Cl as the central atom):
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Cl – O – Cl
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Each Cl has three lone pairs (6 electrons) and shares one single bond with the central O atom. The O atom has two lone pairs and forms single bonds with each Cl atom.
However, in this prompt, Cl is the central atom, so the structure must be drawn differently:
Correct Structure with Cl as Central Atom:
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:Cl:
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O
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:Cl:
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Formal Charges:
To determine formal charges:
Step 1: Count valence electrons.
- Cl has 7 valence electrons
- O has 6 valence electrons
Step 2: Assign bonding and non-bonding electrons.
- Central Cl has 2 single bonds (to O and Cl) and 3 lone pairs
- O has 2 lone pairs and two single bonds
- Terminal Cl has 3 lone pairs and 1 single bond
Formal charge formula:
Formal Charge = (Valence e⁻) – (Nonbonding e⁻ + ½ Bonding e⁻)
- Central Cl: 7 – (6 + 2) = -1
- O: 6 – (4 + 4) = 0
- Terminal Cl: 7 – (6 + 2) = -1
This structure gives formal charges of -1 on both Cl atoms, which is not ideal.
A better structure forms a double bond between Cl and O:
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Cl = O – Cl
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- Left Cl: 3 lone pairs, 1 double bond → 7 – (6 + 2) = -1
- O: 2 lone pairs, 2 bonds → 6 – (4 + 4) = 0
- Right Cl: 3 lone pairs, 1 single bond → 7 – (6 + 2) = -1
This still places negative charges on Cl atoms, which is acceptable due to chlorine’s ability to expand its octet.
This molecule is not ideally represented with Cl as the central atom. Oxygen is more electronegative and smaller, making it more suited for the center. Assigning Cl to the center results in less stable formal charge distribution
