Draw the Lewis structure for XeF4 . Is the molecule polar or nonpolar? What is the electronic geometry, molecular geometry, and hybridization of xenon? Lastly, draw the 3-D structure of the entire molecule.
The Correct Answer and Explanation is:
Lewis Structure of XeF₄:
The xenon tetrafluoride (XeF₄) molecule consists of one xenon (Xe) atom and four fluorine (F) atoms. Xenon is in Group 18, meaning it has 8 valence electrons. Fluorine is in Group 17 and each fluorine atom contributes 7 valence electrons.
- Step 1: Xenon (Xe) contributes 8 electrons, and each fluorine (F) contributes 7, so the total valence electrons are: 8(fromXe)+4×7(fromF)=36 valence electrons.8 (from Xe) + 4 \times 7 (from F) = 36 \text{ valence electrons}.8(fromXe)+4×7(fromF)=36 valence electrons.
- Step 2: Place the fluorine atoms around the xenon atom. Each fluorine will form a single bond with xenon, using 8 electrons (4 bonds × 2 electrons per bond).
- Step 3: Distribute the remaining electrons (36 total – 8 used in bonds = 28 electrons) as lone pairs on the fluorine atoms. Each fluorine atom will have 3 lone pairs, consuming 24 electrons (4 fluorines × 6 electrons = 24 electrons).
- Step 4: Place the remaining 4 electrons as lone pairs on xenon. Xenon will have 2 lone pairs, which completes the 36 valence electrons.
Lewis structure for XeF₄:
F
|
F — Xe — F
|
F
Xenon is the central atom with four fluorine atoms bonded to it.
Polarity:
XeF₄ is nonpolar. Despite having polar bonds (because of the high electronegativity difference between xenon and fluorine), the molecular geometry is square planar. The symmetry of the molecule ensures that the dipoles cancel out, resulting in no net dipole moment.
Electronic Geometry, Molecular Geometry, and Hybridization:
- Electronic Geometry: The electronic geometry of XeF₄ is octahedral. This is because xenon has six regions of electron density around it: four bonding pairs and two lone pairs.
- Molecular Geometry: Due to the two lone pairs, the molecular geometry is square planar. This shape results from the repulsion between the bonding pairs and lone pairs, arranging the fluorine atoms in a flat, square configuration.
- Hybridization: Xenon undergoes sp³d² hybridization to form six hybrid orbitals (four for bonding with fluorine and two for lone pairs). This is consistent with the octahedral electron geometry.
3-D Structure of XeF₄:
To represent the 3-D structure, imagine a square with fluorine atoms at each corner, and xenon at the center. The two lone pairs of electrons on xenon are positioned opposite each other, causing the fluorine atoms to lie in the same plane.
I’ll now generate a 3-D model based on this description.
