Name: Nobelium
Symbol: No
Atomic Number: 102
Atomic Weight: 259.000000
Family: Rare Earth Elements
CAS RN: 10028-14-5
Description: A radioactive rare earth metal.
State (25C): Solid
Oxidation states: +2, +3

Molar Volume: unknown
Valence Electrons: 5f147s2

Boiling Point: unknown
Melting Point: 1100oK, 827oC, 1520oF

Elec. Energy Level: 2, 8, 18, 32, 32, 8, 2
Isotopes: 17 + None Stable + 4 meta states
Heat of Vaporization:  unknown
Heat of Fusion: unknown
Density: unknown
Specific Heat: unknown
Atomic Radius: 285 pm
Ionic Radius: 1.1
Electronegativity: 1.3 (Pauling), 1.2 (Allrod Rochow)
1s2 2s2p6 3s2p6d10 4s2p6d10f14 5s2p6d10f14 6s2p6 7s2


Nobelium (named forAlfred Nobel, discoverer of dynamite).  In 1957 physicists at the Nobel Institute of Physics in Stockhlom, Sweden, announced that they had synthesized an isotope of element 102.  The team reported that they created an isotope with a half-life of 10 minutes at 8.5 MeV after bombarding 244Cm with 13C nuclei.  Based on this report, the Commission on Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) assigned and accepted the name nobelium and the symbol No for the "new" element.  Subsequent Russian and American efforts to repeat the experiment failed.

The acceptance of the name was premature, for both Russian and American efforts now completely rule out the possibility of any isotope of nobelium having a half-life of 10 min in the vicinity of 8.5 MeV.  Early work in 1957 on the search for this element, in Russia at the Kurchatov Institute, was marred by the assignment of 8.9 +/- 0.4 MeV alpha radiation with a half-life of 2 to 40 sec, which was too indefinite to support claim to discovery.

In 1958, another group of scientists, Albert Ghiorso, Glenn T. Seaborg, Torbrn Sikkeland and John R. Walton, working at the Lawrence Radiation Laboratory in Berkeley, California, attempted to confirm the Nobel Institute's discovery. They were unable to produce any isotope of nobelium with a half-life of 10 minutes.  They were able to produce nobelium-254, with a half-life of three seconds, by bombarding curium-246 with carbon-12, using a new double-recoil technique.  A  new heavy-ion linear accelerator (HILAC) was used to bombard a thin target of curium (95% 244Cm and 4.5% 246Cm) with 12C ions to produce 102No according to the 246Cm (12C, 4n) reaction.

A third group, working at the Joint Institute for Nuclear Reserch in Dubna, Russia, also could not duplicate the Nobel Institute's work but were able to confirm the Berkeley group's work. Credit for discovering nobelium was eventually given to the scientists working at Lawrence Radiation Laboratory, who decided to keep the name nobelium.   Today, the Lawrence Radiation Laboratory is known as the Lawrence Berkeley Laboratory.

In 1966 researchers at the University of California, Berkeley, confirmed the 1958 experiments and went on to show the existence of 254No (half-life 55 s), 252No (half-life 2.3 s), and 257No (half-life 23 s).  In view of the discover's traditional right to name an element, the Berkeley group, in 1967, suggested that the hastily given name nobelium, along with the symbol No, be retained.

Nobelium's most stable isotope, nobelium-259, has a half-life of about 58 minutes. It decays into fermium-255 through alpha decay or into mendelevium-259 through electron capture.

Since only tiny amounts of nobelium have ever been produced, there are currently no uses for it outside of basic scientific research.

Nobelium was the most recent element "of which the news had come to Harvard" when Tom Lehrer wrote "The Elements Song " and was therefore the element with the highest atomic number to be included.

2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f14
5s2 5p6 5d10 5f14
6s2 6p6


Little is known about nobelium and only small quantities of it have ever been produced.   It has no known uses whatsoever outside of the laboratory.  Its most stable isotope, 259No, has a half-life of 58 minutes and decays to 255Fm through alpha decay or to 259Md through electron capture.


17 radioisotopes of nobelium have been characterized, with the most stable being 259No with a half-life of 58 minutes, 255No with a half-life of 3.1 minutes, and 253No with a half-life of 1.7 minutes.  All of the remaining radioactive isotopes have half-lives that are less than 56 seconds, and all of these have half-lives that are less than 2.4 seconds.  This element also has 4 meta state, 251mNo (t 1.7 seconds), 252mNo (t 26 days), 253mNo (t 31 s), 254mNo (t 0.28 seconds).

The known isotopes of nobelium range in atomic weight from 248.08660 amu (248No) to 264.11235 amu (264No).  The primary decay mode before the most stable isotope, 259No, is alpha emission, and the primary mode after is spontaneous fission.  The primary decay products before 259No are element 100 (fermium) isotopes, and the primary products after are energy and subatomic particles.

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Atomic Mass
248No 248.08660 <2 s
249No 249.08783 57 s
250No 250.08751 5.7 s
251No 251.08901 0.78 seconds
251mNo   1.7 seconds
252No 252.088977 2.27 seconds
252mNo   26 days
253No 253.09068 1.62 minutes
253mNo   31 s
254No 254.090955 51 seconds
254mNo   0.28 seconds
255No 255.093241 3.1 minutes
256No 256.094283 2.91 seconds
257No 257.096877 25 seconds
258No 258.09821 1.2 ms
259No 259.10103 58 minutes
260No 260.10264 106 ms
261No 261.10575 ~3 hours
262No 262.10730 ~5 ms
263No 263.11055 ~20 minutes
264No 264.11235 ~1 minutes

atom.gif (700 bytes)

Nobelium Data


Atomic Structure

Atomic Radius (): 285 pm
Atomic Volume: unknown
Covalent Radius: unknown
Crystal Structure: unknown
Ionic Radius: 1.1

Chemical Properties

Electrochemical Equivalent: 4.83 g/amp-hr
Electron Work Function: unknown
Electronegativity: 1.3 (Pauling), 1.2 (Allrod Rochow)
Heat of Fusion: unknown
First Ionization Potential: unknown
Second Ionization Potential: unknown
Third Ionization Potential: unknown
Valence Electron Potential (-eV): unknown
Ionization Energy (eV): 6.65 eV

Physical Properties

Atomic Mass Average: unknown
Boiling Point: unknown
Melting Point: 1100oK, 827oC, 1520oF
Heat of Vaporization: unknown
Coefficient of Lineal Thermal Expansion/K-1:
Electrical Conductivity: unknown
Thermal Conductivity: unknown
Density: unknown
Enthalpy of Atomization: unknown
Enthalpy of Fusion: unknown
Enthalpy of Vaporization: unknown
Molar Volume: unknown
Specific Heat: unknown
Vapor Pressure: unknown
Estimated Crustal Abundance: unknown
Estimated Oceanic Abundance: unknown