Question

Helium's subshell electron configuration is 1s². But why helium not included on S Block elements?

Answer 1

Helium's chemical properties are more similar to the p-block noble gases due to its full shell. It is a stable element and does not take place in the chemical reaction similar to the noble gases like Neon, Argon etc. which are there in the p block. So, even if Helium has the electronic configuration of 1s² , it is not included with the s block elements.