Noble gases are completely inert and cannot form stable chemical compounds.

The noble gases earned their reputation honestly. Helium, neon, argon, krypton, xenon, and radon have filled outer electron shells and showed extraordinarily little chemical reactivity under ordinary conditions. For decades they were commonly called the inert gases.

That description gradually hardened into an absolute rule: noble gases could not form stable compounds.

Neil Bartlett challenged it in 1962. He noticed that platinum hexafluoride was powerful enough to oxidize oxygen and reasoned that xenon, with a comparable ionization energy, might also react. The resulting xenon compound broke the supposed prohibition.

Chemists quickly developed a wider xenon chemistry, including fluorides and oxides, and later identified compounds involving other noble gases under suitable conditions.

The discovery did not make the group normally reactive. Helium and neon remain extraordinarily resistant to ordinary chemistry, and even xenon requires conditions and partners very different from those of typical reactive elements.

The correction is to completely inert. A filled valence shell strongly suppresses reaction; it does not make chemical bonding impossible.