The first gap was eventually filled by element 43, technetium 1, with the second gap being filled by element 75, rhenium. Rhenium was the first of these two new group-7-elements to be discovered ...

The official discovery of element-43 is accorded to Emilio Segrè and co-workers. Technetium, as they called it, was the last of elements 1-92 to be tracked down, and in fact it had to be ...