Technetium

Symbol: Tc
Atomic number: 43
Category: transition metals
Group: 7
Period: 5
Block: d
Atomic weight: [98] g/mol
Electrons per shell: 2, 8, 18, 13, 2
CAS number: 7440-26-8
Phase: solid
Density: 11 kg/l (near room temperature)
Melting point: 2430 K (2157C, 3915F)
Boiling point: 4538 K (4265C, 7709F)
Crystal structure: hexagonal
Oxidation states: 7, 6, 5, 4, 3, 1
Electronegativity: 1.9 (Pauling scale)
Name's origin: technitos (Greek)
Name's meaning: artificial, since technetium was the first element to be artificially produced
Facts:
- on Earth, technetium occurs in trace but measurable quantities as a product of spontaneous fission in uranium ore or by neutron capture in molybdenum ores
- is a silvery-grey radioactive metal with an appearance similar to platinum
- plays no natural biological role and is not normally found in the human body
- technetium-98 has a half-life of 4.2 million years
- technetium-99m (the m indicates that this is a metastable nuclear isomer) is used in radioactive isotope medical tests, for example as a radioactive tracer that medical equipment can detect in the human body