Question

why do helium has zero valency?

Answer 1

Helium has 0 valency because the electron is 2 for helium and  the outer most shell is fully filled .... that is K shell contain 2 , so the valency is 0 for helium and it is known as noble gases or inert gases . its has extremely low reactive .
 
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Answer 2

Answer:

helium has zero valency bcoz electron is two for helium and outermost shell is fully filled that is k shell contains 2 so valency is zero for helium and it is known as noble gases or inert gases it has extremely low reactivity..

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