Concept: Dipole moment is a measure of the polarity of a molecule. A molecule has a zero dipole moment if its individual bond dipoles cancel each other out due to its symmetrical geometry. This often occurs in molecules with highly symmetrical structures where the central atom has no lone pairs or where lone pairs are symmetrically arranged.

Why (A) is correct:

1. Determine the hybridization and geometry of XeF₂:

• Xenon (Xe) is the central atom. It has 8 valence electrons.
• Two fluorine (F) atoms form single bonds with Xe.
• Number of bond pairs = 2.
• Number of lone pairs = (8 - 2)/2 = 3.
• Total electron pairs = 2 (bond pairs) + 3 (lone pairs) = 5.
• This corresponds to sp³d hybridization.
• The electron geometry is trigonal bipyramidal.
• To minimize repulsion, the lone pairs occupy the equatorial positions, and the bond pairs occupy the axial positions.
• This arrangement results in a linear molecular geometry for XeF₂.
• In a linear molecule like XeF₂, the two Xe-F bond dipoles are equal in magnitude and opposite in direction, thus canceling each other out. Therefore, XeF₂ has a zero dipole moment.

Option Analysis:

• A) XeF₂: As explained above, it has a linear geometry with sp³d hybridization, leading to a zero dipole moment.
• B) XeF₃: This compound does not exist as a stable neutral molecule. Xenon typically forms even-numbered fluorides (XeF₂, XeF₄, XeF₆).
• C) XeF₄: XeF₄ has sp³d² hybridization and a square planar molecular geometry. While it is symmetrical, the individual bond dipoles cancel out, resulting in a zero dipole moment. However, the question asks for the fluoride with zero dipole moment, and XeF₂ is also a valid answer. In multiple-choice questions, if only one option is to be selected, XeF₂ is a common example. If both were options and only one could be chosen, there might be ambiguity, but here XeF₂ is a clear case. (Note: XeF₄ also has zero dipole moment, but XeF₂ is given as the correct answer, implying it's the intended primary example or the only one among the choices that fits the criteria if others were polar).
• D) XeF₆: XeF₆ has sp³d³ hybridization. It has 6 bond pairs and 1 lone pair. Its molecular geometry is distorted octahedral (or pentagonal bipyramidal with one position occupied by a lone pair), which is asymmetrical due to the presence of the lone pair. Therefore, XeF₆ has a non-zero dipole moment.

Given the options and the typical context of such questions, XeF₂ is a classic example of a molecule with a zero dipole moment due to its linear geometry.

Correct Answer: (A)