Atomic number:43

Group numbers:7

Period:5

Electronic configuration:[Kr] 4d⁶ 5s¹

Formal oxidation number:+4 +6 +7

Electronegativities:2.1

Atomic radius / pm:135.2

Relative atomic mass:[98]

 

Technetium was discovered by Carlo Perrier (IT) and Emilio Segré (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.

Density / g dm^-3:11500 (est., 293 K)

Molar volume / cm³mol^-1:8.52 (est., 293 K)

Electrical resistivity / μΩcm:16.9 (20 °C)

Thermal conductivity / W m^-1K^-1:50.6

Melting point / °C:2157

Boiling point / °C:4265

Heat of fusion / kJ mol^-1:23.81

Heat of vaporization / kJ mol^-1:585.22

Heat of atomization / kJ mol^-1:678

1st ionization energy / kJ mol^-1:702.42

2nd ionization energy / kJ mol^-1:1472.38

3rd ionization energy / kJ mol^-1:2850.20

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:-