Mendelevium

Mendelevium, 101Md
Mendelevium
Pronunciation
Mass number[258]
Mendelevium in the periodic table
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 Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver 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 Gold Mercury (element) Thallium Lead 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 Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Tm

Md

(Upp)
fermiummendeleviumnobelium
Atomic number (Z)101
Groupf-block groups (no number)
Periodperiod 7
Block  f-block
Electron configuration[Rn] 5f13 7s2
Electrons per shell2, 8, 18, 32, 31, 8, 2
Physical properties
Phase at STPsolid (predicted)
Melting point1100 K ​(800 °C, ​1500 °F) (predicted)
Density (near r.t.)10.3(7) g/cm3 (predicted)[1][a]
Atomic properties
Oxidation states+2, +3
ElectronegativityPauling scale: 1.3
Ionization energies
  • 1st: 636 kJ/mol
  • [2]
Other properties
Natural occurrencesynthetic
Crystal structureface-centered cubic (fcc)
Face-centered cubic crystal structure for mendelevium

(predicted)[1]
CAS Number7440-11-1
History
Namingafter Dmitri Mendeleev
DiscoveryLawrence Berkeley National Laboratory (1955)
Isotopes of mendelevium
Main isotopes[3] Decay
abun­dance half-life (t1/2) mode pro­duct
256Md synth 1.17 h ε 256Fm
257Md synth 5.52 h ε 257Fm
α 253Es
SF
258Md synth 51.5 d α 254Es
ε 258Fm
β 258No
259Md synth 1.60 h SF
α 255Es
260Md synth 31.8 d SF
α 256Es
ε 260Fm
β 260No
 Category: Mendelevium
| references

Mendelevium is a synthetic chemical element; it has symbol Md (formerly Mv) and atomic number 101. A metallic radioactive transuranium element in the actinide series, it is the first element by atomic number that currently cannot be produced in macroscopic quantities by neutron bombardment of lighter elements. It is the third-to-last actinide and the ninth transuranic element. It can only be produced in particle accelerators by bombarding lighter elements with charged particles. Seventeen isotopes are known; the most stable is 258Md with half-life 51 days; however, the shorter-lived 256Md (half-life 1.17 hours) is most commonly used in chemistry because it can be produced on a larger scale.

Mendelevium was discovered by bombarding einsteinium with alpha particles in 1955, the method still used to produce it today. It was named after Dmitri Mendeleev, father of the periodic table of the chemical elements. Using available microgram quantities of einsteinium-253, over a million mendelevium atoms may be made each hour. The chemistry of mendelevium is typical for the late actinides, with a preponderance of the +3 oxidation state but also an accessible +2 oxidation state. All known isotopes of mendelevium have short half-lives; there are currently no uses for it outside basic scientific research, and only small amounts are produced.

  1. ^ a b Fournier, Jean-Marc (1976). "Bonding and the electronic structure of the actinide metals". Journal of Physics and Chemistry of Solids. 37 (2): 235–244. Bibcode:1976JPCS...37..235F. doi:10.1016/0022-3697(76)90167-0.
  2. ^ Sato, Tetsuya K.; Asai, Masato; Borschevsky, Anastasia; Beerwerth, Randolf; Kaneya, Yusuke; Makii, Hiroyuki; Mitsukai, Akina; Nagame, Yuichiro; Osa, Akihiko; Toyoshima, Atsushi; Tsukada, Kazuki; Sakama, Minoru; Takeda, Shinsaku; Ooe, Kazuhiro; Sato, Daisuke; Shigekawa, Yudai; Ichikawa, Shin-ichi; Düllmann, Christoph E.; Grund, Jessica; Renisch, Dennis; Kratz, Jens V.; Schädel, Matthias; Eliav, Ephraim; Kaldor, Uzi; Fritzsche, Stephan; Stora, Thierry (25 October 2018). "First Ionization Potentials of Fm, Md, No, and Lr: Verification of Filling-Up of 5f Electrons and Confirmation of the Actinide Series". Journal of the American Chemical Society. 140 (44): 14609–14613. doi:10.1021/jacs.8b09068.
  3. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.


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