* Atoms with eight valence electrons are stable: This is true, thanks to the octet rule. Having a full outer shell of eight electrons makes them very unreactive.

* They don't easily form compounds: Since they are already stable, they don't readily react with other atoms to form compounds. Noble gases, like Helium (He), Neon (Ne), and Argon (Ar), are prime examples of this. They exist as single atoms and are very unreactive.

However, there are a few exceptions:

* Some elements in the p-block can form compounds: Elements like oxygen (O) and sulfur (S) can have more than eight valence electrons in some compounds. This is due to the presence of expanded octets, where the valence electrons can occupy d-orbitals.

* Elements can gain or lose electrons: Some elements can gain or lose electrons to achieve a full outer shell of eight. This is how ionic compounds are formed. For example, sodium (Na) loses an electron to become Na+, while chlorine (Cl) gains an electron to become Cl-.

In summary: While atoms with eight valence electrons are stable and less likely to form compounds, they can participate in reactions, especially those that involve expanding the octet or forming ionic bonds.