Final answer:
The noble gases, except helium, have a full valence shell of eight electrons, making them stable and unreactive.
Step-by-step explanation:
The noble gases, including helium, neon, argon, krypton, xenon, and radon, possess a specific number of valence electrons. In general, the noble gases have a full valence shell of eight electrons, except for helium, which has a full valence shell of two electrons. This full valence shell makes them very stable and unreactive, earning them the name 'noble' gases.