Page 50 - Curriculum Visions Dynamic Book

Yttrium (Y)
Element 39.A silvery-coloured metal belonging to the rare-earth metals (lanthanides) in the Periodic Table. Powdered yttrium ignites spontaneously in air.
Discovery
Discovered by the Finnish scientist Johan Gadolin (whose name is remembered
in the element gadolinium) in 1794. However, the element was isolated by Carl Gustav Mosander only in 1843.
First called yttria, after the nearby town of Ytterby, Sweden (a rich source of many rare-earth minerals), it was subsequently renamed yttrium. It was the first rare earth to be discovered.
Technology
Yttrium is used in metal alloys, and yttrium oxide makes the red dots (phosphors) on colour television tubes.
Yttrium aluminium garnet is a gemstone that looks like a diamond. It is also used in glass and ceramics because it helps make them shock resistant. It has a coefficient of expansion similar to glass. Yttrium can be a catalyst and is added to alloys to increase the strength of metals such as chromium. Radioactive yttrium can treat cancer.
Geology
Yttrium is never found as a native element, but is mainly combined with other rare earths in the minerals gadolinite, euxenite and xenotime. Yttrium was also found in samples
of lunar rock collected on the Apollo missions.
Biology
Yttrium is not found in living things. It is, however, not thought to be harmful.
Key facts...
Name: yttrium
Symbol: Y
Atomic number: 39
Atomic weight: 88.9
Position in Periodic Table: transition metal,
group (3) (scandium group); period 5 State at room temperature: solid Colour: silvery
Density of solid: 4.46 g/cc
Melting point: 1,523°C
Boiling point: 3,337°C
Origin of name: named after the town Ytterby, in
Sweden
Shell pattern of electrons: 2–8–18–9–2
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