1. Draw the Lewis Dot structure of RnCl2
2. Identify and name the atom geometry for this molecule.
3. State whether the molecule is polar or non-polar.
The Correct Answer and Explanation is :
1. Lewis Dot Structure of RnCl₂
Radon dichloride (RnCl₂) consists of a radon (Rn) atom bonded to two chlorine (Cl) atoms. Since radon is a noble gas, it has a complete octet (eight valence electrons), but in this compound, it forms bonds with two chlorine atoms. The Lewis structure follows the octet rule, where:
- Radon (Rn): 8 valence electrons
- Chlorine (Cl): 7 valence electrons each
Each chlorine atom forms a single bond with radon, fulfilling chlorine’s octet. The radon atom will have three lone pairs of electrons.
Here is the Lewis dot structure:
- Radon (Rn) in the center
- Two chlorine (Cl) atoms on either side, each sharing one electron with Rn
- Three lone pairs of electrons on Rn
- Three lone pairs of electrons on each Cl
I will generate an image of the Lewis structure.
2. Molecular Geometry of RnCl₂
The molecular geometry of RnCl₂ is determined using the VSEPR (Valence Shell Electron Pair Repulsion) Theory.
- Electron domains: The radon atom has two bonding pairs (with chlorine) and three lone pairs.
- Electron geometry: Trigonal Bipyramidal (considering lone pairs)
- Molecular shape: Linear, because the three lone pairs repel each other into an equatorial position, leaving the two chlorine atoms in a straight line with the radon atom.
3. Polarity of RnCl₂
The polarity of a molecule depends on its shape and the electronegativity difference between the atoms.
- Electronegativity:
- Radon (Rn) has an electronegativity of 2.2.
- Chlorine (Cl) has an electronegativity of 3.16.
- The electronegativity difference is 3.16 – 2.2 = 0.96, indicating a polar bond.
However, because RnCl₂ has a linear shape, the dipole moments of the two polar Rn-Cl bonds cancel out symmetrically. This results in a non-polar molecule overall.
Conclusion
Even though Rn-Cl bonds are polar due to the difference in electronegativity, the overall molecule is non-polar due to its linear shape, which cancels out dipole moments. The molecule follows VSEPR theory, where the lone pairs around radon push the chlorine atoms into a straight-line configuration.
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