The monatomic gases, also known as noble gases, are:

* Helium (He)

* Neon (Ne)

* Argon (Ar)

* Krypton (Kr)

* Xenon (Xe)

* Radon (Rn)

These elements exist as single atoms in their gaseous state under standard conditions. They are unreactive due to their full outer electron shells, making them very stable.