For ClO3+ and ClO2, draw the lewis structure and determine the following:
Type of hybrid orbitals on chlorine atom
Number of hybrid orbitals used in overlap with atomic orbitals
Number of hybrid orbitals accommodating unshared electrons
Electron domain geometry
Molecular geometry
The correct answer and explanation is :
Lewis Structures of ( \text{ClO}_3^+ ) and ( \text{ClO}_2 )
1. Chlorine Trioxyl cation (ClO₃⁺)
Step-by-step construction of the Lewis structure:
- Chlorine (Cl) is the central atom with 7 valence electrons.
- Oxygen (O) has 6 valence electrons, and there are 3 oxygen atoms, giving a total of 18 valence electrons.
- For ( \text{ClO}_3^+ ), we subtract 1 electron due to the positive charge, leaving us with 24 valence electrons.
- Chlorine is bonded to three oxygens in the trioxyl cation.
- The Lewis structure involves three single bonds between Cl and O, with lone pairs placed on the oxygen atoms. One oxygen is assigned a double bond to chlorine to minimize formal charge and maintain octets for the oxygens.
Lewis structure:
[
\text{Cl} – \text{O} – \text{O} – \text{O}
]
(With formal charges adjusted appropriately).
2. Chlorine Dioxide (ClO₂)
Step-by-step construction of the Lewis structure:
- Chlorine (Cl) has 7 valence electrons.
- Oxygen (O) has 6 valence electrons, and there are 2 oxygen atoms, so we have 12 valence electrons.
- For ( \text{ClO}_2 ), no charge is involved, and the total number of valence electrons is 19.
- Chlorine forms a bond with each oxygen, but we must place lone pairs on oxygen atoms.
Lewis structure:
[
\text{Cl} = \text{O} – \text{O}
]
(With formal charges adjusted appropriately).
Hybridization and Molecular Properties
ClO₃⁺ (Chlorine Trioxyl cation)
- Type of hybrid orbitals on chlorine atom:
- Chlorine in ( \text{ClO}_3^+ ) undergoes sp² hybridization because it forms three bonds with oxygen atoms, which suggests three electron domains around the chlorine atom.
- Number of hybrid orbitals used in overlap with atomic orbitals:
- Chlorine uses 3 hybrid orbitals to overlap with the p-orbitals of the oxygen atoms.
- Number of hybrid orbitals accommodating unshared electrons:
- There are 0 unshared electron pairs on chlorine, as all valence electrons are involved in bonding.
- Electron domain geometry:
- The electron domain geometry is trigonal planar because there are three bonding regions around the chlorine.
- Molecular geometry:
- The molecular geometry is trigonal planar, as there are no lone pairs on the chlorine atom.
ClO₂ (Chlorine Dioxide)
- Type of hybrid orbitals on chlorine atom:
- Chlorine in ( \text{ClO}_2 ) undergoes sp² hybridization, forming two sigma bonds with oxygen atoms and leaving one lone pair.
- Number of hybrid orbitals used in overlap with atomic orbitals:
- Chlorine uses 2 hybrid orbitals to overlap with the p-orbitals of oxygen atoms.
- Number of hybrid orbitals accommodating unshared electrons:
- There is 1 lone pair on chlorine, occupying one hybrid orbital.
- Electron domain geometry:
- The electron domain geometry is trigonal planar, with three electron regions: two bonding pairs and one lone pair.
- Molecular geometry:
- The molecular geometry is bent or V-shaped, due to the presence of one lone pair on chlorine.
Explanation:
- Hybridization is determined by the number of bonds and lone pairs. Chlorine in both species adopts sp² hybridization due to the three electron domains (bonds and lone pairs).
- Electron domain geometry is influenced by the number of regions around the chlorine atom; hence, both molecules show trigonal planar geometry.
- Molecular geometry differs slightly due to lone pairs. In ( \text{ClO}_3^+ ), there are no lone pairs, so the geometry is trigonal planar. In ( \text{ClO}_2 ), a lone pair causes a bent structure.
Thus, both molecules have trigonal planar electron domain geometries but different molecular shapes due to the presence of lone pairs.