Relative atomic mass: [98]

English: Technetium
French: Technetium
Croatian: Tehnecij
German: Technetium
Italian: Tecnezio
Spanish: Tecnecio

Atomic number: 43
Group numbers: 7
Period: 5
Standard state (20 oC): solid

Discovery: 1937 Carlo Perrier (IT), Emilio Segre (US)
Technetium was discovered by Carlo Perrier (IT) and Emilio Segre (US) in 1937. The origin of the name comes from the Greek word technikos meaning artificial. It is a silvery-grey metal that resists oxidation but tarnishes in moist air and burns in high oxygen environment. Technetium is the first synthetically produced element. It is also radioactive. Technetium is made by bombarding molybdenum with deuterons (heavy hydrogen) in a cyclotron. Added to iron in quantities as low as 55 part-per-million transforms the iron into a corrosion-resistant alloy.
Electronic configuration: [Kr] 4d6 5s1
Formal oxidation number: +4 +6 +7
Atomic radius: 135.2 pm

Electronegativities: 2.1
Thermal conductivity: 50.6 W/(m K)
Electrical resistivity (20 oC): 16.9 microOhm cm

Melting point: 2157 oC
Boiling point: 4265 oC

Heat of fusion: 23.81 kJ/mol
Heat of vaporization: 585.22 kJ/mol
Heat of atomization: 678 kJ/mol

42Mo <= 43Tc => 44Ru

ASCII Periodic Table of the Elements
29 Aug. 2017
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