What is the Lewis dot structure for XeF5(+)? What is it’s molecular shape? Polar or non polar? What is the hybridization of the central atom?
The correct answer and explanation is:
Sure! Let’s break down the Lewis dot structure, molecular shape, polarity, and hybridization of the XeF₅⁺ ion step by step.
1. Lewis Dot Structure for XeF₅⁺
- Central atom: Xenon (Xe), a noble gas with 8 valence electrons.
- Fluorine atoms: Each fluorine (F) atom has 7 valence electrons.
- Total valence electrons:
- Xe: 8 electrons
- 5 F atoms: 5 × 7 = 35 electrons
- Positive charge (+): subtract 1 electron
Total = 8 + 35 – 1 = 42 valence electrons
- Bonding: Each Xe–F bond uses 2 electrons, so 5 bonds = 10 electrons used.
- Remaining electrons = 42 – 10 = 32 electrons, placed as lone pairs on the F atoms and the central Xe.
- XeF₅⁺ has one lone pair on the Xe (because Xe can expand its octet), meaning the Xe is surrounded by 5 bonding pairs and 1 lone pair.
2. Molecular Shape
- Electron pairs around Xe: 5 bonding + 1 lone = 6 electron pairs.
- Electron pair geometry for 6 pairs is octahedral.
- With one lone pair, the molecular shape becomes square pyramidal.
So, XeF₅⁺ has a square pyramidal shape.
3. Polarity
- The shape (square pyramidal) is asymmetrical due to the lone pair.
- The bond dipoles of Xe–F do not cancel out perfectly.
- Therefore, XeF₅⁺ is polar.
4. Hybridization of the Central Atom (Xe)
- 6 electron pairs → corresponds to sp³d² hybridization.
- The Xe atom uses one s, three p, and two d orbitals to accommodate bonding and lone pairs.
Summary
| Aspect | Answer |
|---|---|
| Lewis structure | Xe central with 5 F atoms bonded + 1 lone pair on Xe |
| Molecular shape | Square pyramidal |
| Polarity | Polar |
| Hybridization | sp³d² |
Explanation (300 words)
The ion XeF₅⁺ consists of a xenon atom bonded to five fluorine atoms and carries a positive charge. Xenon, a noble gas, has 8 valence electrons but can expand its octet by using its d orbitals. Each fluorine contributes 7 valence electrons, and since the ion is positively charged, one electron is subtracted from the total count.
When drawing the Lewis structure, five Xe–F single bonds are formed, using 10 electrons. The remaining electrons are assigned as lone pairs on the fluorines and xenon. Xenon, being central, has one lone pair after bonding with five fluorines.
The six electron pairs (5 bonding + 1 lone) around Xe adopt an octahedral electron pair geometry. However, the molecular shape considers only the positions of atoms, not lone pairs. Removing one vertex for the lone pair changes the shape to square pyramidal. This is a less symmetrical shape compared to a perfect octahedron.
The asymmetry causes the bond dipoles not to cancel out completely, making XeF₅⁺ a polar molecule. The lone pair also slightly distorts bond angles, reducing symmetry further.
Hybridization corresponds to the number of electron pairs around the central atom. For six electron pairs, the hybridization is sp³d², meaning the xenon atom uses one s, three p, and two d orbitals for bonding and lone pair accommodation.
In summary, the Lewis structure of XeF₅⁺ shows xenon bonded to five fluorines with one lone pair, resulting in a square pyramidal shape. Its polarity arises from this asymmetry, and its hybridization is sp³d² due to the six electron pairs.