ChemistryMediumClass 12

Group 18 — Noble gases, properties, compounds of Xe

p-block Elements (Class 12 — Groups 15, 16, 17, 18)

JEE Qs

Hard

min

Master the hybridization, VSEPR geometries, and hydrolysis reactions of xenon compounds, as these are frequently tested with specific details.

🧮 Key Formulas

General electronic configuration: ns²np⁶ (except He: 1s²)

Xe + F2 (excess) --400°C, 1 bar--> XeF2 (Linear, sp³d)

Xe + 2 F2 (1:5 ratio) --600°C, 6 bar--> XeF4 (Square planar, sp³d²)

Xe + 3 F2 (1:20 ratio) --300°C, 60-70 bar--> XeF6 (Distorted octahedral, sp³d³)

XeF6 + H2O → XeOF4 + 2 HF (Partial hydrolysis)

XeF6 + 2 H2O → XeO2F2 + 4 HF (Partial hydrolysis)

XeF6 + 3 H2O → XeO3 + 6 HF (Complete hydrolysis)

XeF4 + 12 H2O → 2 Xe + XeO3 + 24 HF + 3 O2 (Hydrolysis)

XeO3 (Pyramidal, sp³)

XeOF4 (Square pyramidal, sp³d²)

XeO2F2 (See-saw, sp³d)

XeO4 (Tetrahedral, sp³)

1Noble gases are generally unreactive due to high ionization enthalpy, high positive electron gain enthalpy, and stable ns²np⁶ configuration (octet rule satisfaction, except He: 1s²).
2Helium's inertness, low density, and low boiling point (<4.2K) are crucial for its applications in cryogenics, deep-sea diving (diluting O₂), and MRI magnets.
3Xenon forms compounds primarily with fluorine and oxygen (and sometimes with both) due to its larger size and comparatively lower ionization enthalpy, making its valence electrons more easily removed. Kr forms only KrF₂.
4VSEPR theory and hybridization (sp³d, sp³d², sp³d³, sp³) are essential for predicting the exact shapes and geometries of xenon compounds, including lone pair repulsion.
5Hydrolysis reactions of xenon fluorides are critical: XeF₄ produces Xe, XeO₃, HF, and O₂; XeF₆ yields XeO₃ (complete hydrolysis) or XeOF₄/XeO₂F₂ (partial hydrolysis), along with HF.

✕Incorrectly predicting the hybridization and geometry of xenon compounds (e.g., XeF₆ is distorted octahedral, not perfect octahedral due to lone pair).
✕Confusing the products of different hydrolysis reactions of xenon fluorides, especially partial vs. complete hydrolysis of XeF₆.
✕Ignoring the specific conditions (temperature, pressure, reactant ratio) required for the synthesis of different xenon fluorides.