Technetium

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.

Technetium, ₄₃Tc

Technetium
Pronunciation	/tɛkˈniːʃiəm/ ​(tek-NEE-shee-əm)
Mass number	[97]
Technetium in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium Mn ↑ Tc ↓ Re molybdenum ← technetium → ruthenium
Atomic nummer (Z)	43
Group	group 7
Period	period 5
Block	d-block
Element category	Transeetion metal
Electron confeeguration	[Kr] 4d5 5s2
Electrons per shell	2, 8, 18, 13, 2
Pheesical properties
Phase at STP	solit
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	−3, −1, 0, +1, +2, +3, +4, +5, +6, +7 strangly acidic
Electronegativity	Pauling scale: 1.9
Atomic radius	empirical: 136 pm
Covalent radius	147±7 pm
Colour lines in a spectral range Spectral lines o technetium
Ither properties
Creestal 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)
Diskivery	Carlo Perrier an Emilio Segrè (1937)
First isolation	Carlo Perrier an Emilio Segrè (1937)
Main isotopes o technetium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 95mTc syn 61 d ε 95Mo γ - IT 95Tc 96Tc syn 4.3 d ε 96Mo γ - 97Tc syn 2.6×106 y ε 97Mo 97mTc syn 91 d IT 97Tc 98Tc syn 4.2×106 y β− 98Ru γ - 99Tc trace 2.111×105 y β− 99Ru 99mTc syn 6.01 h IT 99Tc γ -

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 year auld, helped bolster the theory that starns can produce hivier elements.