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It's Elemental

The Element Mendelevium

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101 Md Mendelevium 258

Atomic Number: 101

Atomic Weight: 258

Melting Point: 1100 K (827°C or 1521°F)

Boiling Point: Unknown

Density: Unknown

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 7

Group Number: none

Group Name: Actinide

Special Notes: Radioactive and Artificially Produced

What's in a name? Named after the Russian chemist Dmitri Mendeleyev.

Say what? Mendelevium is pronounced as men-deh-LEE-vee-em.

History and Uses:

Mendelevium was first produced by Stanley G. Thompson, Glenn T. Seaborg, Bernard G. Harvey, Gregory R. Choppin and Albert Ghiorso working at the University of California, Berkeley, in 1955. They bombarded atoms of einsteinium-253 with helium ions using a device known as a cyclotron. This produced atoms of mendelevium-256, an isotope with a half-life of about 77 minutes, and a free neutron.

Mendelevium's most stable isotope, mendelevium-258, has a half-life of about 51.5 days. It decays into einsteinium-254 through alpha decay or decays through spontaneous fission.

Since only small amounts of mendelevium have ever been produced, it currently has no uses outside of basic scientific research.

Estimated Crustal Abundance: Not Applicable

Estimated Oceanic Abundance: Not Applicable

Number of Stable Isotopes: 0 (View all isotope data)

Ionization Energy: 6.58 eV

Oxidation States: +3, +2

Electron Shell Configuration:


2s2   2p6

3s2   3p6   3d10

4s2   4p6   4d10   4f14

5s2   5p6   5d10   5f13

6s2   6p6


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For questions about this page, please contact Steve Gagnon.