How do we know promethium exists?
I believe it has an atomic number of 61 Promethium – (Prometheus, who, according to mythology, stole fire from heaven). The existence of promethium was first predicted by Bohuslav Brauner in 1902; this prediction was supported by Henry Mosely in 1914, who developed an x-ray method for determining integer atomic numbers of elements and found a gap for a missing element which would have atomic number 61, but was unknown (however, Moseley of course had no sample of the element to verify this). Historical claims for the discovery of element 61 create an interesting trail from around 1925 in Florence (suggested name: florentium) to America in 1926 (suggested name: illinium). None of the claims, however, could be substantiated and today we know they were not simply a result of fleetingly small samples but rather poor work. While spectral lines of promethium are evident in the light from some stars, it now seems apparent that no promethium is found in accessible areas of the earth–hence the
