Page 35 - Curriculum Visions Dynamic Book

Mg see Magnesium; Mn see Manganese
Molybdenum (Mo)
Key facts...
Name: molybdenum
Symbol: Mo
Atomic number: 42
Atomic weight: 95.94
Position in Periodic Table: transition metal,
group (6) (chromium group); period 5 State at room temperature: solid Colour: silvery-grey
Density of solid: 10.2 g/cc
Melting point: 2,610°C
Boiling point: 5,560°C
Origin of name: from the Greek word
molybdos for lead, because it looks like
lead
Shell pattern of electrons: 2–8–18–13–1
Element 42. A rare, silvery-grey and hard metal belonging to the transition metals in the Periodic Table. It was often confused with graphite and lead ore.
Discovery
Carl William Scheele discovered it in 1778 in a sample of the ore now known as molybdenite. It was thought to be an ore of lead at that time.
Technology
Molybdenum makes an alloy that strengthens and increases the melting point of steel. It also improves corrosion resistance. It goes into electrodes in electrically heated glass
furnaces. It has an important role
as a catalyst in petroleum refining and is a good fuel additive that can lubricate the upper cylinder head of a combustion engine and so increase fuel efficiency. It can also be made into a filament for heating wires.
Geology
Molybdenum is not found as a native element.The most important ore is molybdenite (molybdenum sulphide, MoS2).
Biology
Molybdenum is an essential trace element in all living things.A lack of it can make
a soil infertile, while its presence helps bacteria fix nitrogen in the soil.
 The Climax Mine, high in the Colourado Rockies, is the largest source of molybdenite – the principal ore of molybdenum.
Molybdenum also appears in other ores and is often recovered as a by-product of non-ferrous copper refining.
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