Helium’s lone energy shell has two electrons.
The valence shells of Argon and Neon each have eight electrons.
The elements have little inclination to mix with other elements because they contain the most electrons in their valence shells (resulting in stable duplet and octet configurations).
As a result, the valency of Helium, Neon, and Argon is zero.
Final answer:
Hence, Helium, Neon and Argon have zero valency as they contain maximum electrons in their valence shells.