Noble gases are generally considered unreactive. This is because they have a full outer shell of electrons, making them very stable and unlikely to gain or lose electrons.

However, there are a few exceptions:

* Xenon (Xe) is the most reactive of the noble gases. It can form compounds with fluorine, oxygen, and other highly electronegative elements.

* Krypton (Kr) is less reactive than xenon but can also form compounds with fluorine.

* Radon (Rn) is even less reactive than krypton, but it can form compounds as well.

The reactivity of noble gases increases as you go down the group (from helium to radon). This is because the outermost electrons become less tightly bound to the nucleus, making them more susceptible to interaction with other atoms.

While noble gases are generally considered unreactive, their ability to form compounds under certain conditions highlights the fact that even the most stable elements can participate in chemical reactions.