Technetium

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Technetium,  43Tc
General properties
Name, symbol Technetium, Tc
Appearance Silvery metallic
Technetium in the periodic table
Mn

Tc

Re
Molybdenum ← Technetium → Ruthenium
Atomic number 43
Standard atomic weight (Ar) 98.907
Group, block 7; d-block
Period period 5
Electron configuration [Kr] 4d5 5s2
per shell
2, 8, 18, 13, 2
Physical properties
Phase Solid
Density near r.t. 11 g/cm3
Heat of fusion 33.29 kJ/mol
Heat of 585.2 kJ/mol
Molar heat capacity 24.27 J/(mol·K)
 pressure
Atomic properties
Oxidation states −3, −1, 0, +1, +2, +3, +4, +5, +6, +7
Electronegativity Pauling scale: 1.9 (Pauling scale)
energies 1st: 702 kJ/mol
2nd: 1470 kJ/mol
3rd: 2850 kJ/mol
Atomic radius empirical: 136 pm
Covalent radius 147±7 pm
Miscellanea
Speed of sound thin rod 16,200 m/s (at 20 °C)
Thermal expansion 7.1 µm/(m·K) (at 20°C)
Thermal conductivity 50.6 W/(m·K)
Electrical resistivity 200 Ω·m (at 20 °C)
Magnetic ordering Paramagnetic
CAS Registry Number 7440-26-8
History
Prediction Dmitri Mendeleev ((1871))
Discovery and first isolation Emilio Segrè and Carlo Perrier (1937)
· references

Technetium is a radioactive, grey metal with the atomic number 43. It is the lightest element that has no stable isotopes.

Properties

Chemical

The chemical properties of technetium lie in between those of manganese and rhenium. It has 9 oxidation states, the most common oxidation states of technetium are +4, +5, and +7.

Physical

Technetium is a silvery radioactive metal.

Availability

Technetium is very rare and expensive. Bulk amounts of technetium are near impossible to obtain.

However, one can obtain it from certain element collector supplies as plated on metal foils. The price range is usually 400-1000€ for technetium plated foil.

Isolation

To do

Projects

  • Element collection

Handling

Safety

Technetium has low chemical toxicity, but ingestion or inhalation is very dangerous since it leads to radiation poisoning.

Storage

The Tc99 isotope can be stored in closed glass bottles, or, preferably, ampoules. All the other more active isotopes should be stored in containers with thick lead walls.

Disposal

To do

References

Relevant Sciencemadness threads