Technetium
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General properties | |||||
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Name, symbol | Technetium, Tc | ||||
Appearance | Silvery metallic | ||||
Technetium in the periodic table | |||||
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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) | ||||
Technetium is a radioactive, grey metal with the atomic number 43. It is the lightest element that has no stable isotopes.
Contents
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