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Noble gases (He, Ne, Ar, Kr, Xe, Rn) have completely filled valence shells (ns^{2np}^6, He: 1). Their chemical inertness arises from very high IE and no tendency to gain electrons.
Xenon forms compounds because it has the lowest IE among stable noble gases and large polarisable electron cloud. Xe-F bonds are strong enough for stability.
XeF2: linear (sp3d, 3 lone pairs). XeF4: square planar (sp3d2, 2 lone pairs). XeF6: distorted octahedral (sp3d3, 1 lone pair). Hydrolysis: XeF2 gives Xe + HF + O2; XeF4 gives mixed products; XeF6 gives XeO3 + HF.
XeO3 is trigonal pyramidal (sp3, 1 lone pair), highly explosive. XeOF4 is square pyramidal (sp3d2). XeOF2 is T-shaped (sp3d).
He and Ne form no stable compounds (IE too high). Ar forms only weak van der Waals complexes. KrF2 exists but is less stable than Xe compounds.
Noble gas applications: He (balloons, cooling), Ne (neon signs), Ar (welding shield gas), Kr (photography flash), Xe (anaesthesia, headlights), Rn (cancer treatment, radon testing in buildings).