Rare-earth element

Columns: Z | Symbol | Name | Etymology | Selected applications | Abundance ( ppm )
64 | Gd | Gadolinium | after Johan Gadolin ( 1760-1852 ) , to honor his investigation of rare earths | High refractive index glass or garnets , lasers , X-ray tubes , computer memories , neutron capture , MRI contrast agent , NMR relaxation agent , magnetostrictive alloys such as Galfenol , steel additive | 6.2 | 65 | Tb | Terbium | after the village of Ytterby , Sweden | Additive in Neodymium based magnets , green phosphors , lasers , fluorescent lamps ( as part of the white triband phosphor coating ) , magnetostrictive alloys such as terfenol-D , naval sonar systems , stabilizer of fuel cells | 1.2 | 66 | Dy | Dysprosium | from the Greek dysprositos , meaning hard to get | Additive in Neodymium based magnets , lasers , magnetostrictive alloys such as terfenol-D , hard disk drives | 5.2 | 67 | Ho | Holmium | after Stockholm ( in Latin , Holmia ) , native city of one of its discoverers | Lasers , wavelength calibration standards for optical spectrophotometers , magnets | 1.3 | 68 | Er | Erbium | after the village of Ytterby , Sweden | Infrared lasers , vanadium steel , fiber-optic technology | 3.5 | 69 | Tm | Thulium | after the mythological northern land of Thule | Portable X-ray machines , metal-halide lamps , lasers | 0.52 | 70 | Yb | Ytterbium | after the village of Ytterby , Sweden | Infrared lasers , chemical reducing agent , decoy flares , stainless steel , stress gauges , nuclear medicine , monitoring earthquakes | 3.2 | 71 | Lu | Lutetium | after Lutetia , the city that later became Paris | Positron emission tomography - PET scan detectors , high-refractive-index glass , lutetium tantalate hosts for phosphors , catalyst used in refineries , LED light bulb | 0.8

Example questions:
The rare-earth element known as yttrium is named after a village on which island ? | What is the abundance in ppm of the rare-earth element that was found in 1879 using spectral analysis ? | What is the abundance in ppm of the rare-earth element that was discovered by Carl Gustav Mosander ? | What is the abundance in ppm of the most reactive lanthanide among the rare-earth elements ?

Answers:
Resarö | 22 | 39 | 2