Technetium

Technetium,  ₄₃Tc

General properties
Name, seembol	technetium, Tc
Pronunciation	/tɛkˈniːʃiəm/ tek-NEE-shee-əm
Technetium in the periodic cairt
Mn ↑ Tc ↓ Re molybdenum ← technetium → ruthenium
Atomic nummer (Z)	43
Group, block	group 7, d-block
Period	period 5
Element category	transeetion metal
Staundart atomic wicht (Ar)	[98]
Electron configuration	[Kr] 4d5 5s2
per shell	2, 8, 18, 13, 2
Pheesical properties
Phase	solid
Meltin pynt	2430 K ​(2157 °C, ​3915 °F)
Bylin pynt	4538 K ​(4265 °C, ​7709 °F)
Density near r.t.	11 g/cm3
Heat o fusion	33.29 kJ/mol
Heat o vapourisation	585.2 kJ/mol
Molar heat capacity	24.27 J/(mol·K)
vapour pressur (extrapolatit) P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2727 2998 3324 3726 4234 4894
Atomic properties
Oxidation states	7, 6, 5, 4, 3, 2, 1, -1, -3 ​strangly acidic oxide
Electronegativity	Pauling scale: 1.9
Atomic radius	empirical: 136 pm
Covalent radius	147±7 pm
Miscellanea
Crystal structur	​hexagonal close-packed (hcp)
Speed o soond thin rod	16,200 m/s (at 20 °C)
Thermal conductivity	50.6 W/(m·K)
Magnetic orderin	Paramagnetic
CAS Nummer	7440-26-8
History
Prediction	Dmitri Mendeleev (1871)
Discovery	Carlo Perrier an Emilio Segrè (1937)
First isolation	Carlo Perrier an Emilio Segrè (1937)
Maist stable isotopes o technetium
iso NA hauf-life DM DE (MeV) DP 95mTc syn 61 d ε - 95Mo γ 0.204, 0.582, 0.835 - IT 0.0389, e 95Tc 96Tc syn 4.3 d ε - 96Mo γ 0.778, 0.849, 0.812 - 97Tc syn 2.6×106 y ε - 97Mo 97mTc syn 91 d IT 0.965, e 97Tc 98Tc syn 4.2×106 y β− 0.4 98Ru γ 0.745, 0.652 - 99Tc trace 2.111×105 y β− 0.294 99Ru 99mTc syn 6.01 h IT 0.142, 0.002 99Tc γ 0.140 -

Technetium is the chemical element wi atomic number 43 an seembol Tc. It is the lawest atomic number element wioot ony stable isotopes; every fairm o it is radioactive. Nearly aw technetium is produced synthetically, an anly minute amoonts are foond in naitur. Naiturally occurrin technetium occurs as a spontaneous fission product in uranium ore or bi neutron capture in molybdenum ores. The chemical properties o this sillery gray, crystalline transeetion metal are intermediate atween rhenium an manganese.

Mony o technetium's properties wur predictit bi Dmitri Mendeleev afore the element wis discovered. Mendeleev notit a gap in his periodic table an gae the undiscovered element the provisional name ekamanganese (Em). In 1937, technetium (specifically the technetium-97 isotope) acame the first predominantly airtificial element tae be produced, hence its name (frae the Greek τεχνητός, meanin "airtificial").

Its short-lived gamma ray-emitting nuclear isomer—technetium-99m—is uised in nuclear medicine for a wide variety o diagnostic tests. Technetium-99 is uised as a gamma ray-free soorce o beta pairticles. Lang-lived technetium isotopes produced commercially are bi-products o fission o uranium-235 in nuclear reactors an are extractit frae nuclear fuel rods. Acause na isotope o technetium haes a hauf-life langer than 4.2 million years (technetium-98), its detection in 1952 in red giants, which are billions o years auld, helped bolster the theory that starns can produce hivier elements.