Page 38 - Curriculum Visions Dynamic Book

Cd see Cadmium Cerium (Ce)
Element 58. Cerium is one of the rare-earth metals (lanthanides) in the Periodic Table. Cerium is iron-grey and is about as soft as tin.
Although cerium is not widely known, it is as common in the Earth’s crust as copper.
Cerium is (apart from Europium) the most reactive of the rare-earth metals. It oxidises quickly in moist air and decomposes rapidly in hot water.The metal can ignite when scratched with a knife. It is attacked by both acids and alkalis.
Discovery
Cerium was discovered in Sweden in 1803 by Jöns Jacob Berzelius,Wilhelm Hisinger and Martin Klaproth.
Technology
It is used for fine polishing of glass (it is faster than rouge), to make porcelain more opaque and to clear colour impurities from glass. It is also widely applied as an alloying
metal, for example, in jet engines, where it raises the melting point of the alloy. It goes into incandescent gas mantles and
catalysts in self-cleaning oven walls.
Geology
Cerium is never found as a native element.The main cerium minerals are allanite, monazite, cerite and bastanite.
Cerium is difficult to isolate because it is chemically similar to the other
lanthanides, and most lanthanide minerals contain thorium, which is radioactive.
Key facts...
Name: cerium
Symbol: Ce
Atomic number: 58
Atomic weight: 140.1
Position in Periodic Table: inner transition metal;
period 6 (lanthanide series)
State at room temperature: solid
Colour: iron-grey
Density of solid: 6.771 g/cc
Melting point: 798°C
Boiling point: 3,424°C
Origin of name: named after the asteroid Ceres,
which had been discovered in 1801. Shell pattern of electrons: 2–8–18–20–8–2
Biology
Cerium is not found in living things, but is not thought to be particularly harmful.
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