How would someone in 1917 describe elements 43, 61, 72, 75, 84, 85, 87, 89, and 91?
Unknown elements were discussed according to Mendeleiev's nomenclature. The prefix eka- was used for the element just under a known element, and it was dvi- for the following one, two lines under. For example, the element 31 under aluminum was celled eka-aluminum, just before it was discovered as gallium. With this same technique, the element 43 was named eka-manganese before it was discovered as technetium, and element 75 was dvi-manganese before its discovery as rhenium.
In your list, the element 61 was not expected. The 72 was eka-zirconium. The radioactive elements (Z &gt; 83) were not expected.
Ref. : M. Fontani, M. Costa, M. Orna, The Lost Elements, Oxford University Press 2015, 530 p., ISBN 978-0-19-938334-4.