"Shells" are composed of individual orbitals. The valence shell is the outer most shell and only its s and p orbitals are occupied, which is why the octet rule works. The relationship between group configurations and group members are as follows:
Group 1 & 2- ns1,2
Group 1-13 - (n-1)d1-10 ns0-2
Group 13-18 - ns2np1-6
