if the elements have similar electron configurations , then the elements will be grouped into same family / group on the periodic table of elements
pairing is grouping. electron_shell is not group. electron_shell is group. group has identity_element scale is homogeneous_structure. pairing_objects is not grouping. mixture is homogeneous_structure. molecule is group_of_similar_atoms. scale is not homogeneous_structure. pairing_objects is grouping.