p-Block Elements (Group 15–18) · Question 8

Based on VSEPR model, match the xenon compounds given in List-I with the corresponding geometries and the number of lone pairs on xenon given in List-II and choose the correct option.

1. P-5, Q-2, R-3, S-1
2. P-5, Q-3, R-2, S-4
3. P-4, Q-3, R-2, S-1
4. P-4, Q-2, R-5, S-3

Answer

(2) P-5, Q-3, R-2, S-4

Solution

Electron-pair geometry follows from (bond pairs + lone pairs) on Xe; π bonds of Xe=O are not counted.

XeF2: 2 bp + 3 lp = 5 → trigonal bipyramidal, three lone pairs → 5.

XeF4: 4 bp + 2 lp = 6 → octahedral, two lone pairs → 3.

XeO3: 3 σ bp + 1 lp = 4 → tetrahedral, one lone pair → 2.

XeO3F2: 5 σ bp + 0 lp → trigonal bipyramidal, no lone pair → 4.

P-5, Q-3, R-2, S-4

Answer: (B)