Mendelevium
| Mendelevium | ||||||||||||||||||||||||||||||||||||||||
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| Pronunciation |
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| Mass number | [258] | |||||||||||||||||||||||||||||||||||||||
| Mendelevium in the periodic table | ||||||||||||||||||||||||||||||||||||||||
| Atomic number (Z) | 101 | |||||||||||||||||||||||||||||||||||||||
| Group | f-block groups (no number) | |||||||||||||||||||||||||||||||||||||||
| Period | period 7 | |||||||||||||||||||||||||||||||||||||||
| Block | f-block | |||||||||||||||||||||||||||||||||||||||
| Electron configuration | [Rn] 5f13 7s2 | |||||||||||||||||||||||||||||||||||||||
| Electrons per shell | 2, 8, 18, 32, 31, 8, 2 | |||||||||||||||||||||||||||||||||||||||
| Physical properties | ||||||||||||||||||||||||||||||||||||||||
| Phase at STP | solid (predicted) | |||||||||||||||||||||||||||||||||||||||
| Melting point | 1100 K (800 °C, 1500 °F) (predicted) | |||||||||||||||||||||||||||||||||||||||
| Density (near r.t.) | 10.3(7) g/cm3 (predicted)[1][a] | |||||||||||||||||||||||||||||||||||||||
| Atomic properties | ||||||||||||||||||||||||||||||||||||||||
| Oxidation states | common: +3 +2[2] | |||||||||||||||||||||||||||||||||||||||
| Electronegativity | Pauling scale: 1.3 | |||||||||||||||||||||||||||||||||||||||
| Ionization energies |
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| Other properties | ||||||||||||||||||||||||||||||||||||||||
| Natural occurrence | synthetic | |||||||||||||||||||||||||||||||||||||||
| Crystal structure | face-centered cubic (fcc) (predicted)[1] | |||||||||||||||||||||||||||||||||||||||
| CAS Number | 7440-11-1 | |||||||||||||||||||||||||||||||||||||||
| History | ||||||||||||||||||||||||||||||||||||||||
| Naming | after Dmitri Mendeleev | |||||||||||||||||||||||||||||||||||||||
| Discovery | Lawrence Berkeley National Laboratory (1955) | |||||||||||||||||||||||||||||||||||||||
| Isotopes of mendelevium | ||||||||||||||||||||||||||||||||||||||||
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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-last actinide, the ninth transuranic element, and the first transfermium; it is named after Dmitri Mendeleev, the father of the periodic table.
Like all the transfermiums, it can only be produced in particle accelerators by bombarding lighter elements with charged particles. The element was first produced in 1955 by bombarding einsteinium with alpha particles, the method still used today. Using commonly-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 dominant +3 oxidation state but also a +2 oxidation state accessible in solution. 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.
- ^ 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.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.
- ^ 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.
- ^ 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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