[113] As recently as 2007, some companies continued to manufacture and sell thorium mantles without giving adequate information about their radioactivity, with some even falsely claiming them to be non-radioactive. [46] This helps the compound remain solid in a flame, and it considerably increases the brightness of the flame; this is the main reason thorium is used in gas lamp mantles. Chemical symbol for Thorium is Th. [30][31] Ionium–thorium dating is a related process, which exploits the insolubility of thorium (both 232Th and 230Th) and thus its presence in ocean sediments to date these sediments by measuring the ratio of 232Th to 230Th. Element Thorium (Th), Group 20, Atomic Number 90, f-block, Mass 232.038. This table gives information about some radiosotopes of thorium, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments. [121][122][123] India has projected meeting as much as 30% of its electrical demands through thorium-based nuclear power by 2050. Melting point: 3,182 degrees Fahrenheit (1,750 degrees Celsius) 7. National Library of … For other isotopes, the isotopic mass usually differs and is usually within 0.1 u of the mass number. [140] Yellowed lenses may be restored to their original colourless state by lengthy exposure to intense ultraviolet radiation. No chemical toxicity has yet been observed in the tracheobronchial tract and the lungs from exposure to thorium. [55], In an acidic aqueous solution, thorium occurs as the tetrapositive aqua ion [Th(H2O)9]4+, which has tricapped trigonal prismatic molecular geometry:[56][57] at pH < 3, the solutions of thorium salts are dominated by this cation. Alkaline earth metal carbonates may be removed after reaction with hydrogen chloride; then follow thickening, filtration, and calcination. Melting Point: 1750.0 °C (2023.15 K, 3182.0 °F) Boiling Point: 4790.0 °C (5063.15 K, 8654.0 °F) Number of Protons/Electrons: 90. The chemical symbol for Thorium is Th. Today, liquid solvent extraction procedures involving selective complexation of Th4+ are used. The mixture is then cooled to 70 °C and diluted with ten times its volume of cold water, so that any remaining monazite sinks to the bottom while the rare earths and thorium remain in solution. 1) You may use almost everything for non-commercial and educational use. Most of the isotope data on this site has been obtained from the National Nuclear Data Center.Please visit their site for more information.. Isotopes With A … The closeness in energy levels of the 5f, 6d, and 7s energy levels of thorium results in thorium almost always losing all four valence electrons and occurring in its highest possible oxidation state of +4. Thorium's radioactivity was widely acknowledged during the first decades of the 20th century. [28][29], Two radiometric dating methods involve thorium isotopes: uranium–thorium dating, based on the decay of 234U to 230Th, and ionium–thorium dating, which measures the ratio of 232Th to 230Th. The major impurity is usually thorium dioxide (ThO2); even the purest thorium specimens usually contain about a tenth of a percent of the dioxide. [161] Most of the radiation dose by a normal user arises from inhaling the radium, resulting in a radiation dose of up to 0.2 millisieverts per use, about a third of the dose sustained during a mammogram. Illustration about Name, Symbol, Atomic Mass and Atomic Number of the Period Table Element of Thorium. Atomic weight (average mass of the atom): 232.0 4. If the end product of this radioactive element is an isotope of lead of atomic mass 208 and atomic number 82 then the number of alpha and beta particles emitted in its decay are__ [125] They concluded that a 233U-fired bomb would be a very potent weapon, but it bore few sustainable "technical advantages" over the contemporary uranium–plutonium bombs,[126] especially since 233U is difficult to produce in isotopically pure form. Common thorium compounds are also poorly soluble in water. [65] Because of the abrupt loss of stability past 209Bi, the r-process is the only process of stellar nucleosynthesis that can create thorium and uranium; all other processes are too slow and the intermediate nuclei alpha decay before they capture enough neutrons to reach these elements. For 12C the atomic mass is exactly 12u, since the atomic mass unit is defined from it. Name: Thorium. [10], In deep seawaters the isotope 230Th makes up to 0.04% of natural thorium. The major impurity is commonly thorium … [63][65][h] In the distant past the abundances of thorium and uranium were enriched by the decay of plutonium and curium isotopes, and thorium was enriched relative to uranium by the decay of 236U to 232Th and the natural depletion of 235U, but these sources have long since decayed and no longer contribute. Our Privacy Policy is a legal statement that explains what kind of information about you we collect, when you visit our Website. It is transparent to electromagnetic waves having wavelengths in the range of 0.350–12 µm, a range that includes near ultraviolet, visible and mid infrared light. [93] Metallic thorium was isolated for the first time in 1914 by Dutch entrepreneurs Dirk Lely Jr. and Lodewijk Hamburger. Symbol: Th. Review 2000 (IUPAC Technical Report)", "Atomic weights of the elements 2005 (IUPAC Technical Report)", "AREVA Med launches production of lead-212 at new facility", "An efficient chelator for complexation of thorium-227", "Solution Thermodynamics and Kinetics of Metal Complexation with a Hydroxypyridinone Chelator Designed for Thorium-227 Targeted Alpha Therapy", "Engineered Recognition of Tetravalent Zirconium and Thorium by Chelator–Protein Systems: Toward Flexible Radiotherapy and Imaging Platforms", "Energy splitting in the ground state doublet in the nucleus, "Evaluation of nuclear criticality safety data and limits for actinides in transport", Institut de radioprotection et de sûreté nucléaire, "Ground Levels and Ionization Potentials for Lanthanide and Actinide Atoms and Ions", "Hydrated metal ions in aqueous solution: How regular are their structures? This is due to relativistic effects, which become stronger near the bottom of the periodic table, specifically the relativistic spin–orbit interaction. [60] It is unstable in air and decomposes in water or at 190 °C. [4], Thorium metal has a bulk modulus (a measure of resistance to compression of a material) of 54 GPa, about the same as tin's (58.2 GPa). [146] All 233U production methods result in impurities of 232U, either from parasitic knock-out (n,2n) reactions on 232Th, 233Pa, or 233U that result in the loss of a neutron, or from double neutron capture of 230Th, an impurity in natural 232Th:[150], 232U by itself is not particularly harmful, but quickly decays to produce the strong gamma emitter 208Tl. [96][97] Cerium was soon removed from the main body of the table and placed in a separate lanthanide series; thorium was left with group 4 as it had similar properties to its supposed lighter congeners in that group, such as titanium and zirconium. [29] This parallels the uranium fuel cycle in fast breeder reactors where 238U undergoes neutron capture to become 239U, beta decaying to first 239Np and then fissile 239Pu. [124], During the Cold War the United States explored the possibility of using 232Th as a source of 233U to be used in a nuclear bomb; they fired a test bomb in 1955. Thorium is a chemical element with atomic number 90 which means there are 90 protons and 90 electrons in the atomic structure. [149], The used fuel is difficult and dangerous to reprocess because many of the daughters of 232Th and 233U are strong gamma emitters. Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Atomic Mass: 232.0381 amu. Thorium 228 [46] Thorium has no known biological role. As a result, handling small amounts of thorium, such as those in gas mantles, is considered safe, although the use of such items may pose some risks. [46] The other natural thorium isotopes are much shorter-lived; of them, only 230Th is usually detectable, occurring in secular equilibrium with its parent 238U, and making up at most 0.04% of natural thorium. Our Website follows all legal requirements to protect your privacy. [106] 10,000 individuals in the United States had been injected with thorium during X-ray diagnosis; they were later found to suffer health issues such as leukaemia and abnormal chromosomes. The properties of thorium depend highly on a number of impurities present in the sample. This reflected the belief at that time that thorium and the rare-earth metals were divalent. Illustration of electron, fluorine, laboratory - 178286554 Pure thorium is very ductile and, as normal for metals, can be cold-rolled, swaged, and drawn. The chemical symbol for Thorium is Th. [46], In 1815, the Swedish chemist Jöns Jacob Berzelius analysed an unusual sample of gadolinite from a copper mine in Falun, central Sweden. Thorium forms the monocapped trigonal prismatic anion [Th(CH3)7]3−, heptamethylthorate, which forms the salt [Li(tmeda)]3[ThMe7] (tmeda= Me2NCH2CH2NMe2). It can take as much as thirty years after the ingestion of thorium for symptoms to manifest themselves. Phase at room temperature: Solid 6. [78], In nature, thorium occurs in the +4 oxidation state, together with uranium(IV), zirconium(IV), hafnium(IV), and cerium(IV), and also with scandium, yttrium, and the trivalent lanthanides which have similar ionic radii. If it undergoes alpha particle emission, the resulting nuclei will be Answer: Radium with mass number-228 and atomic number-88. Uranium -238 usually decays into this isotope of thorium (although in rare cases it can undergo spontaneous fission instead). Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided. Thorium-228. [77] In thorium silicate minerals, the Th4+ and SiO4−4 ions are often replaced with M3+ (where M= Sc, Y, or Ln) and phosphate (PO3−4) ions respectively. [157] Thorium's low solubility in water also means that excretion of thorium by the kidneys and faeces is rather slow. » Boiling Point » Melting Point » Abundant » State at STP » Discovery Year Alvin Radkowsky of Tel Aviv University in Israel was the head designer of Shippingport Atomic Power Station in Pennsylvania, the first American civilian reactor to breed thorium. Atomic Mass of Uranium Atomic mass of Uranium is 238.0289 u. Actinide metal ) for layers the left of protactinium, and 212Bi are released 228Ra 212Pb... 54 ] the hydrides are thermally unstable and readily decompose upon exposure to thorium thorium chalcogenides oxychalcogenides... Independence with their three-stage nuclear power programme which may arise from the use of up to 20.... 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