The 7d transition metals in period 8 are expected to be elements 157 to 166. Although the 8s and 8p 1/2 electrons are bound so strongly in these elements that they should not be able to take part in any chemical reactions, the 9s and 9p 1/2 levels are expected to be readily available for hybridization. These 7d elements should be similar to the 4d elements yttrium through cadmium. In particular, element 164 with a 7d 9s electron configuration shows clear analogies with palladium with its 4d 5s electron configuration.