Page 30 - Curriculum Visions Dynamic Book

Tb see Terbium;Tc see Technetium;Te see Tellurium Technetium (Tc)
Key facts...
Name: technetium
Symbol: Tc
Atomic number: 43
Atomic weight: 99
Position in Periodic Table: transition metal,
group (7) (manganese group); period 5 State at room temperature: solid
Colour: silvery
Density of solid: 11.5 g/cc
Melting point: 2,172°C
Boiling point: 4,877°C
Origin of name: from the Greek word technikos,
meaning artificial
Shell pattern of electrons: 2–8–18–14–1
Element 43.An artificial radioactive silvery metal that belongs to the transition metals in the Periodic Table. It is not very reactive and tarnishes slowly in air.
It was the first element to be artificially produced (see origin of name). It is used as a fuel in nuclear reactors.All of the isotopes (varieties) of technetium are radioactive.
Discovery
Technetium was incorrectly reported as having been discovered in 1925, at which time it was named masurium. It was actually discovered in Italy in 1937 by Carlo Perrier and Emilio Segrè
by bombarding molybdenum with deuteron particles.
Technology
Very small amounts can help steels
resist corrosion. Because technetium is radioactive, this protection can only be given to steels in nuclear reactors and other places where shielding from radioactivity
is possible. Because technetium-99 comes from the fission of uranium in nuclear reactors, relatively large quantities have
now been produced.The element is a very effective corrosion inhibitor for steel and
an excellent superconductor below -262°C.
Geology
Minute amounts have been found on
Earth in molybdenum and uranium ores. The first isolation was in 1962, when technetium-99 was identified in African pitchblende (a uranium-rich ore). However, for all practical purposes it does not exist in
the Earth’s surface rocks. Special telescopes have detected technetium in stars.
Biology
Because it is an artificially produced element, it is not found in living things. Being radioactive, and having the property of binding to living organic molecules, it has the potential to be useful in medicine under controlled conditions. It is used for taking body images because its half-life is short, and so it is not retained in the body.
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