Nobelium (No)
Isotopes of Nobelium
| Isotope | Atomic Mass | Half-life | Mode of Decay | Nuclear Spin |
| No-253 | 253.0907 | 1.70 minutes | α to Fm-249; EC to Md-253 |
9/2 |
| No-254 | 254.0909 | 55 seconds | α to Fm-250; EC to Md-254; SF |
0 |
| No-255 | 255.0932 | 3.10 minutes | α to Fm-251; EC to Md-255 |
1/2 |
| No-256 | 256.0943 | 2.90 seconds | α to Fm-252; AS | 0 |
| No-257 | 257.0968 | 25 seconds | α to Fm-253 | 7/2 |
| No-258 | 258.0983 | 0.0012 seconds | α to Fm-254; SF | 0 |
Nobelium is a radioactive rare earth metal, first correctly identified in 1966 by physicists at the Flerov Laboratory of Nuclear Reactions in Dubna, Soviet Union, although its discovery had been announced by physicists at the Nobel Institute in Sweden in 1957. The synthesis of nobelium was then claimed in April 1958 at the University of California - Berkeley, USA, by Albert Ghiorso, Glenn T. Seaborg, John R. Walton and Torbjørn Sikkeland. It is named after the Swedish chemist Alfred Nobel, who discovered dynamite.
The appearance of this element is unknown; however, it is most likely silvery-white or gray and metallic. If sufficient amounts of nobelium were produced, it would pose a radiation hazard. Twelve radioisotopes of nobelium have been characterized, the most stable being Nobelium-259, with a half-life of 58 minutes.
Properties of Nobelium
| Name | Nobelium |
| Symbol | No |
| Atomic number | 102 |
| Atomic weight | [259] |
| Standard state | Presumably a solid at 298 °K |
| CAS Registry ID | 10028-14-5 |
| Group in periodic table | N/A |
| Group name | Actinoid |
| Period in periodic table | 7 (Actinoid) |
| Block in periodic table | f-block |
| Color | Unknown, but probably metallic and silvery white or grey in appearance |
| Classification | Metallic |
| Melting point | About 1100 °K [or 827 °C or 1521 °F] |
| Boiling point | No data available |
| Electron configuration | [Rn]5f147s2 |
