elements in group 18 have full / complete outer electron shells on the periodic table of elements
one_of_chemical_elements is not helium. group_15_elements is not pnictogens. electron_shell is not group. one_of_chemical_elements is not polonium. electron_shell is group. group_11_elements is coinage_metals. group_11_elements is not coinage_metals. atom is not molecular_component. electron is not particle. one_of_chemical_elements is not iridium.