Question

why He is considered as noble gas even it doesn't have 8 electrons in outermost shell ​

Answer 1

Heya,

Atomic number of He is 2 and hence its configuration is 1s².

Although it has a duplet, it is considered as a noble gas because it is relatively inert in its reaction similar to that of other group 18 members.

Regards

Kshitij

Answer 2

Answer:

Noble gases are the least reactive of all elements. That's because they have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.