Short answers, pulled from the story.
Carl Axel Arrhenius found the heavy black rock in 1787 near the Swedish village of Ytterby. Johan Gadolin identified a new oxide within that sample in 1789 and published his analysis four years later in 1794.
Dissolving mixed oxide ores in sulfuric acid allows fractionation by ion exchange chromatography methods to obtain salts reaching 99.999 percent purity levels. The Bayan Obo deposit in China represents the largest mine since Mountain Pass closure in the 1990s.
Radioisotope yttrium-90 labels drugs edotreotide ibritumomab tiuxetan treating lymphoma leukemia liver ovarian colorectal pancreatic bone cancers. Radioembolization treats hepatocellular carcinoma liver metastasis using millions tiny glass resin beads containing Y-90 microspheres delivered directly blood vessels feeding specific tumors segments lobes.
Yttrium barium copper oxide superconductor developed University Alabama Huntsville Houston 1987 operates above liquid nitrogen boiling point 77.1 Kelvin. This discovery marked second material exhibiting property first achieving superconductivity above economically important nitrogen boiling point.
Only one stable isotope Y-89 occurs naturally in Earth's crust despite group 3 elements having odd atomic numbers. Scandium possesses one stable isotope while yttrium itself has only that single natural occurrence.