Noble gases—including helium, neon, argon, krypton, xenon, and radon—are known for being chemically inert, meaning they rarely form compounds with other elements. This stability comes from their full outer electron shells.
In atomic structure, atoms tend to gain, lose, or share electrons to achieve a stable electron configuration, typically resembling that of the nearest noble gas—a concept known as the octet rule. However, noble gases naturally have this stable configuration:
- Helium has 2 electrons (full first shell),
- The rest (like neon and argon) have 8 electrons in their outermost shell.
Because their outer shells are already full, noble gases have no strong tendency to react with other elements. This makes them ideal for use in applications where chemical non-reactivity is essential—such as neon lights, argon in welding, or helium in balloons and cryogenics.