Page 30 - Curriculum Visions Dynamic Book

Manganese (Mn)
Element 25.A silvery-white,
hard, brittle metal belonging to
the transition metals in the Periodic Table. Manganese is very reactive in air.
Discovery
It was discovered in 1774 by the Swedish chemist Carl Wilhelm Scheele using the mineral pyrolusite (manganese dioxide, MnO2) heated with charcoal (carbon), which smelted the ore and released the metal.
Technology
The main use of manganese is as an alloy to make steel easier to work. Manganese steel is also hard wearing and corrosion resistant. It is also used with steel, aluminium, antimony and copper to make magnets.All aluminium and magnesium
alloys have manganese in them to improve their wearability and corrosion resistance.
Manganese can take away any colour staining in glass that has been tinted by iron impurities.
Potassium permanganate (KMnO4) is a disinfectant.
Geology
Manganese is not found as the free metal in nature. It lends the colour purple to the mineral amethyst and is common in a range of other minerals, some of which
appear abundantly as nodules on the deep ocean floors.
Biology
Manganese compounds are essential to the enzymes that are vital
to all living things.A lack of
manganese causes bone deformities and infertility.
Key facts...
Name: manganese
Symbol: Mn
Atomic number: 25
Atomic weight: 54.94
Position in Periodic Table: transition metal, group
(7) (manganese group); period 4 State at room temperature: solid Colour: silvery-white
Density of solid: 7.44 g/cc
Melting point: 1,246°C
Boiling point: 2,061°C
Origin of name: from the Latin word magnes,
meaning magnet
Shell pattern of electrons: 2–8–13–2
For more on manganese, see Volume 4: Iron, Chromium, and Manganese in the Elements set.
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