Question

the valency of helium is zero what do you understand by that? ​

Answer 1

Valency of helium is 0. It's Valence shell are already filled. So it's stable. It's zero group element. and we know helium is a noble and inert gas. It's non- reactive. It doesn't need to gain or lose electrons because it's already in a stable state.

Answer 2

valency of helium is 2 which loose electron complete it's duplet and become stable . helium have zero valency it means state loses two electron and become stable it may be in in molecular form foreign compound .