Question

For p block elements:

Outermost electronic configuration varies from ns 2 np 1 to ns 2 np 6 in each period

but helium is also present in p block and its electronic configuration is 1s2

so doesnt the OEC vary from ns2 to ns2np6?

Answer 1

Helium is placed in p-block elements in noble gases group due to the fact that it has stable electronic configuration due to its completely filled orbitals like all other noble elments. Thus it does not have the ability to either donate or accept electrons. Consequently these gases are almost chemically inert.