Page 53 - Curriculum Visions Dynamic Book

Pm see Promethium Polonium (Po)
Element 84. Polonium is a radioactive, silvery-grey metalloid in group 6 (the oxygen group) in the Periodic Table. Polonium has more isotopes than
any other element, all of which are radioactive.
Polonium was the first radioactive element to be discovered. It is one of the elements in the uranium–radium series of radioactive decay. Natural polonium is a very rare element.
Key facts...
Name: polonium
Symbol: Po
Atomic number: 84
Atomic weight: 209
Position in Periodic Table: group 6 (16) (oxygen
group; chalcogen); period 6
State at room temperature: solid Colour: silvery-grey
Density of solid: 9.4 g/cc
Melting point: 254°C
Boiling point: 962°C
Origin of name: named after Poland, the
birthplace of Marie Curie
Shell pattern of electrons: 2–8–18–32–18–6
Discovery
It was discovered in 1898 by Pierre and Marie Curie while they were looking for the cause of radioactivity in pitchblende. Marie had to grind up many tonnes
of pitchblende just to get a few tenths
of a gram of polonium. She named the element after her native country, Poland.
In 1934 scientists discovered they could obtain the parent of polonium if
they bombarded natural bismuth with neutrons.That is how it is now prepared, and synthetic polonium is available in commercial quantities.
Technology
Polonium is a good source of alpha radiation because its isotopes disintegrate by emitting alpha particles. It is used as
a source of neutrons and in devices that ionise air in order to reduce electrostatic charge.
Geology
It is found in very tiny amounts in uranium and radium ores. It is obtained as a by-product of radium extraction during uranium ore refining.
Biology
Polonium is not part of living things. However, it is highly radioactive and therefore dangerous to people unless they are protected from it. It emits alpha rays, but these are quite easily shielded using gold foil.That is why it can be used in factories for reducing static electricity.
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