Page 28 - Curriculum Visions Dynamic Book

Bh see Bohrium Bismuth (Bi)
Element 83. Bismuth is hard, brittle and grey-white.
Bismuth is the most metallic
of the elements in group 5 (the nitrogen group) in the Periodic Table. It is one of the heavy metals.
It is notable for its low melting point, its ability to become magnetised, its high electrical resistance and its very low conduction of heat (only mercury conducts less well).Alloys containing more than 55% bismuth expand on freezing.
Technology
Bismuth is used to make low-melting-point alloys, in solders and in automatic sprinkler heads (which have to begin working at
the earliest signs of a fire). For example, Wood’s metal, which is 50% bismuth, 25% lead, 12.5% tin and 12.5% cadmium, has
a melting point as low as 70°C. Bismuth oxide can give a pearly sheen to cast iron and ceramic products. It is
used as a coolant in nuclear reactors because it has a low melting point
but a very high boiling point.
Geology
Native bismuth crystals do occur
in a number of ores but only in small amounts.The most common ore of bismuth is the oxide called bismite (Bi2O3), but most bismuth is obtained as part of the processing of other ores.
Biology
Bismuth is not found naturally in living things. However, traditionally bismuth compounds were used to settle digestive problems and for skin ailments such as eczema. It is also found in haemorrhoid creams.Although it is one of the heavy metals, it is not particularly toxic.
Key facts...
Name: bismuth
Symbol: Bi
Atomic number: 83
Atomic weight: 208.98
Position in Periodic Table: group 5 (15) (nitrogen
group); period 6
State at room temperature: solid
Colour: grey-white with pinkish tinge
Density of solid: 9.75 g/cc
Melting point: 271.3°C
Boiling point: 1,560°C
Origin of name: from the German word bisemutum Shell pattern of electrons: 2–8–18–32–18–5
Discovery
Bismuth has been known since ancient times. It was only identified as an element in its own right in 1740.Today, it is mainly obtained as a by-product of the refining of non-ferrous metals.
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