Periodic Table of the elements main page

Periodic Table

science park

Table of Elements

Chemical information

Science dictionary

scientific data

Site map

Gifts and souvenirs

printable version

go to periodic table










Education Billboard - meet and serve your education needs

Element Fact
Rhenium was the last naturally occurring element to be identified, in 1925. It was so rare that only 1 g of the metal was extracted out of 660 kg of molybdenite ore.

Mendelevium, Md

mendelevium sample

Atomic number: 101
Atomic mass: [258] (no stable nuclide)
Natural abundance: -
Isotopes: -

History and Production

Named after Dmitri Mendeleev (1834-1907), who devised the periodic table of the elements. It was first identified by A. Ghiorso, B.H. Harvey, G.R. Choppin. S.G. Thompson and G.T. Seaborg in 1955, from bomardment of 253Es with helium ions. The isotope produced, 256Md, has a half-life of 78 minutes. Only atomic quantities of the element has been produced. 258Md has the longest half-life of 52 days. It is possible to generate sufficient amount of this isotope to study the chemical properties of mendelevium in solution.

Physical Data

Its physical data is not known since no sizable quantity has ever been produced.

Interatomic distance: -
Melting point: 827C (est.)
Boiling point: n/a
Thermal conductivity/Wm-1K-1: 10 est. (27C)
Density/kgm-3: n/a

Standard Thermodynamic Data (atomic gas)

Enthalpy of formation: -
Gibbs free energy of formation: -
Entropy: -
Heat capacity: -

Electronic data

Electronic configuration: Electronic configuration: [Rn] 5f13 7s2
Term symbol: 2F7/2
Electron affinity: -   Electronegativity (Pauline): -
Ionization energy (first, second, third): 634.874, -, - kJ/mol

Chemical properties

| Copyright | Privacy | Disclaimer | Contact |

2004-2010, all rights reserved.