 The transition metals in period 8 are expected to be elements 157 to 165 (or perhaps with element 121 replacing 157, similarly to the dispute on whether lanthanum or lutetium is better placed as the first 5d transition metal).To these, element 166 may be added to complete the 7d subshell, although like its lighter group 12 homologues, it is questionable if it would show transition metal character.Although the 8s and 8p1/2 electrons are bound so strongly in these elements that they should not be able to take part in any chemical reactions, the 9s and 9p1/2 levels are expected to be readily available for hybridization.