Name: technetium
Symbol: Tc
Atomic number: 43
Atomic weight: [ 98 ]
Group in periodic table: 7
Group name:
Period in periodic table: 5
Block in periodic table: d-block
CAS registry ID: 7440-26-8
Since its discovery, searches for the element technetium in terrestrial materials have been made without success. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars.
Technetium is a silvery-grey metal that tarnishes slowly in moist air. Until 1960, technetium was available only in small amounts. The chemistry of technetium is related to that of rhenium.