Rare Earth Metals Trivia Quiz

Answer:

Rare earth metals (also called "rare earths") are a group of 17 chemical elements: the 15 lanthanides plus scandium and yttrium. The term "rare earth metals" is misleading and dates back to the discovery of these elements. It is based on the fact that they were first found in rare minerals and isolated from them in the form of their oxides (formerly called "earths") but only promethium, a short-lived radioactive element, is truly rare in the Earth's crust. Some of the rare earths, such as cerium, yttrium and neodymium, are more abundant in the Earth's crust than lead, copper or arsenic. Thulium, the rarest stable element of the rare earths, is more abundant than gold or platinum.

However, the term "rare" is justified in that large deposits of economically viable minerals are indeed rare. The elements are usually found in small quantities: in numerous widely dispersed minerals and as impurities in other minerals. Much of the industrial production of rare earth metals is, therefore, a by-product of the chemical processing of other, more concentrated metals from their ores.

Here's a quick breakdown of the 17 elements:

Lanthanum (La): Discovered in 1839 by Carl Gustaf Mosander. It exists primarily in the form of lanthanum oxide (La₂O₃). Known for its high reactivity and softness, it tarnishes quickly when exposed to air. Lanthanum is used in hybrid car batteries, camera lenses and as a catalyst in petroleum refining.

Cerium (Ce): Discovered in 1803 by Martin Klaproth, Jöns Jakob Berzelius and Wilhelm Hisinger. It is most commonly found as cerium oxide (CeO₂). Cerium has variable oxidation states, making it useful in catalytic converters, glass polishing and flint for lighters. It's the most common of the rare earths.

Praseodymium (Pr): Discovered in 1885 by Carl Auer von Welsbach. Its oxide form is praseodymium oxide (Pr₆O₁₁). Praseodymium has excellent magnetic properties and is used in high-strength alloys for aircraft engines, powerful magnets and studio lighting.

Neodymium (Nd): Discovered in 1885 by Carl Auer von Welsbach. It exists mainly as neodymium oxide (Nd₂O₃). Known for its extremely strong magnetic properties, neodymium is critical in the manufacture of powerful magnets used in wind turbines, electric vehicles, headphones and hard drives.

Promethium (Pm): Discovered in 1945 by Jacob Marinsky, Lawrence Glendenin and Charles Coryell. Found as promethium oxide (Pm₂O₃). This radioactive element has a short half-life and is mainly used in nuclear batteries, research and fluorescent paint.

Samarium (Sm): Discovered in 1879 by Paul Émile Lecoq de Boisbaudran. It is commonly found as samarium oxide (Sm₂O₃). Samarium is key to the production of strong permanent magnets and plays a role in nuclear reactors and cancer treatments, particularly for lung and prostate cancer.

Europium (Eu): Discovered in 1901 by Eugène-Anatole Demarçay. It exists mainly as europium oxide (Eu₂O₃). Europium's excellent luminescent properties make it indispensable in phosphorescent and fluorescent applications, including colour displays, LEDs and euro banknotes as an anti-counterfeiting measure.

Gadolinium (Gd): Discovered in 1880 by Jean Charles Galissard de Marignac. Its oxide is gadolinium oxide (Gd₂O₃). Gadolinium is known for its magnetic and neutron-absorbing properties, making it useful in MRI contrast agents and as a shielding material in nuclear reactors.

Terbium (Tb): Discovered in 1843 by Carl Gustaf Mosander. It forms terbium oxide (Tb₄O₇). Terbium emits a bright green light under phosphorescence and is used in solid state devices, fluorescent lamps and the green phosphor in colour television screens.

Dysprosium (Dy): Discovered in 1886 by Paul Émile Lecoq de Boisbaudran. It is usually found as dysprosium oxide (Dy₂O₃). Dysprosium is known for its high magnetic susceptibility and is used in powerful magnets, lasers and nuclear reactor control rods due to its ability to absorb neutrons.

Holmium (Ho): Discovered in 1878 by Marc Delafontaine and Jacques-Louis Soret. It forms mainly holmium oxide (Ho₂O₃). Holmium has the highest magnetic strength of all elements and is used in magnetic fields and nuclear control rods.

Erbium (Er): Discovered in 1842 by Carl Gustaf Mosander. Its oxide is erbium oxide (Er₂O₃). Erbium is important for its pink colour and optical properties, which make it useful in fibre optic communications, lasers and as a colouring agent in glass and porcelain.

Thulium (Tm): Discovered in 1879 by Per Teodor Cleve. It forms mostly thulium oxide (Tm₂O₃). Although rare, thulium is used in X-ray machines, portable radiators and in the manufacture of lasers because of its favourable emission spectrum.

Ytterbium (Yb): Discovered in 1878 by Jean Charles Galissard de Marignac. It occurs as ytterbium oxide (Yb₂O₃). Ytterbium is important for its use in fibre optics, atomic clocks and for improving grain refinement in stainless steel.

Lutetium (Lu): Discovered in 1907 by Georges Urbain, Carl Auer von Welsbach and Charles James. Its oxide is lutetium oxide (Lu₂O₃). Lutetium is dense and stable, making it valuable in PET scan detectors, refinery catalysts and LED light bulbs.

Scandium (Sc): Discovered in 1879 by Lars Fredrik Nilson. It exists primarily as scandium oxide (Sc₂O₃). Scandium is light and strong and is used in aerospace components, sports equipment such as baseball bats and bicycle frames, and in solid oxide fuel cells.

Yttrium (Y): Discovered in 1794 by Johan Gadolin. It forms mostly yttrium oxide (Y₂O₃). Yttrium is key to high temperature stability and is used in superconductors, lasers, ceramics and as a phosphor in CRT displays and LEDs.