The s-block elements are distinguished by the property that in the atomic ground state, the highest-energy electron is found in an s-orbital., These electrons are very easily lost to form positive ions except in helium and hydrogen. The helium configuration is chemically exceedingly stable and thus helium has no known stable compounds; thus it is grouped with the noble gases. https://www.expertsmind.com/chemistry/s-block-elements-homework-assignment-help.aspx