Chemical element, symbol Md and atomic number 101 / From Wikipedia, the free encyclopedia

Dear Wikiwand AI, let's keep it short by simply answering these key questions:

Can you list the top facts and stats about Mendelevium?

Summarize this article for a 10 years old


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.

Quick facts: Mendelevium, Pronunciation, Mass number, Mend...
Mendelevium, 101Md
Mass number[258]
Mendelevium in the periodic table


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][lower-alpha 1]
Atomic properties
Oxidation states+2, +3
ElectronegativityPauling scale: 1.3
Ionization energies
  • 1st: 636 kJ/mol
  • [2]
Other properties
Natural occurrencesynthetic
Crystal structure face-centered cubic (fcc)
Face-centered cubic crystal structure for mendelevium

CAS Number7440-11-1
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
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
Symbol_category_class.svg Category: Mendelevium
| references

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.

Oops something went wrong: