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What is Technetium

A radioactive metal, technetium (pronounced as tek-NEE-she-em) is the first synthetically produced element. Denoted by the chemical symbol Tc, it belongs to the family of transition metals [1].

Technetium Symbol


Origin of its Name: The name of the element is derived from the Greek word ‘tekhnetos’ which means artificial [1].

Who Discovered it: Carlo Perrier and Emilio Segre [1]

When and Where was it Discovered

In the 1920’s, there were claims about its discovery through spectrum analysis. However, nothing was officially confirmed.

In 1937, when Segre in Italy analyzed a molybdenum sample from California that had been subjected to powerful radiation, he isolated a new element that was later named ‘technetium’ from it [1].



Atomic number 43 [1]
CAS number 7440-26-8 [1]
Position in the periodic table [1] Group Period Block
7 5 d

Location of Technetium in the Periodic Table

Properties and Characteristics of Technetium

General Properties

Relative atomic mass [98] [1]
Atomic mass 98 atomic mass units [4]

Physical Properties

Color/appearance Silver [1]
Melting point/freezing point 2157°C (3915°F) [1]
Boiling point 4262°C, 7704°F [1]
Density 11 g/cm3 [1]
State at standard room temperature (solid/liquid/gas) Solid [1]

Chemical Properties

Oxidation state/Oxidation number −3, −1, +1, +2, +3, +4 +5, +6, +7 [1]

Atomic Data of Technetium (Element 43)

Electron configuration (noble gas configuration) [Kr] 4d55s2 [1]
Atomic structure [4]
–          Number of Electrons 43
–          Number of Neutrons 55
–          Number of Protons 43
Radius of atom
       –       Atomic Radius 2.16 Å [1]
       –       Covalent Radius 1.38 Å [1]
Ionization energy [1]


1st 2nd 3rd 4th 5th 6th 7th
702.41 1472.37 2850.18

Technetium Atomic Structure (Bohr Model)

What are the Uses of Technetium

  • It is added to steel in minor amounts to inhibit corrosion and provide protection from long-term damage [1].
  • Technetium-99m, a short-lived isotope of technetium-99 (a byproduct of nuclear weapon explosions) is used as a diagnostic imaging tool for carrying out a sestamibi scan of different parts of the body [1]. Intravenous administration of a gamma-emitting colloid called technetium Tc-99m Sulfur Colloid is done to scan the gastrointestinal system, including liver and spleen [5]. When combined with tetrofosmin, technetium Tc-99m is useful in cardiac imaging after a stress test[6].
  • In hospital and radiopharmacies, technetium tc-99 generators are used to extract medical isotopes [7, 8].
  • Technetium pertechnetate is more effective than radioactive iodine in detecting thyroid abnormalities [9].

Interesting Facts

  • The symbol of the element is depicted by human hand to show that it’s artificially produced [1].

Technetium Cost

Although a radioactive and man-made element, it is commercially available, costing anywhere between $60 and $70 per gram.



One response to “Technetium”

  1. Connor says:

    Thanks for the article! It helped out a lot with my project.

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