Nobelium is a synthetic transuranic element that was discovered in 1996. It is a highly radioactive and unstable element.
History and Discovery
The efforts to synthesize nobelium were carried out by various teams in 1950s and 1960s. In 1957, a team of scientist working at the Nobel Institute of Sweden announced the discovery of new element, 102. They bombarded curium with carbon-13 ions and produced 102, which was named nobelium was given to the newly discovered element. Later, the Joint Institute for Nuclear Research (JINR) reported the successful discovery of the element 102, in 1966. They bombarded neon ions on uranium-238 target and produced nobelium-254 [1]. The name nobelium was given in honor of Alfred Nobel, who invented dynamite. In 1997, the International Union of Pure and Applied Chemistry confirmed the name nobelium for the element 102 [2]. The symbol of nobelium is No.
Nobelium
| Periodic Table Classification | Group n/a Period 7 |
|---|---|
| State at 20C | Solid (predicted) |
| Color | n/a |
| Electron Configuration | [Rn] 5f14 7s2 |
| Electron Number | 102 |
| Proton Number | 102 |
| Electron Shell | 2, 8, 18, 32, 32, 8, 2 |
| Density | 9.9(4) g.cm-3 at 20°C (predicted) |
| Atomic number | 102 |
| Atomic Mass | 259.00 g.mol -1 |
| Electronegativity according to Pauling | 1.30 (predicted) |
Occurrence
Nobelium is an artificial element and does not exist in nature. Small number of atoms of nobelium have been produced till now.
Physical Characteristics
Nobelium is predicted to be a solid under normal conditions. The unstable nature of nobelium and insufficient production of nobelium makes it difficult to carry out a statistically significant analysis of its physical and chemical characteristics. However, various parameters have been predicted so far [3]. The expected density of nobelium is around 9.9 g/cm3. Similarly, the melting point nobelium have been predicted to be 827°C.
Chemical Characteristics
The chemical characteristics of nobelium have not been well studied yet. Nobelium is the tenth tranuranic element and is the second last member of the actinide series. It is expected to have similar properties like barium, when it forms complex with chloride. Nobelium is also predicted to have similarity with strontium in forming organic compounds with oxalate, and citrate. The most common oxidation state of nobelium in aqueous conditions that have been predicted to be +2 and +3. The No+3 is a strong oxidizing agent.
Significance and Uses
- Nobelium is used for research purposes.
Health Effects
Nobelium is a radioactive element and requires special precautions with handling and storage.
Isotopes of Nobelium
There are twelve isotopes of nobelium with mass number ranging from 250-260 and 262. They are unstable and unnatural [4]. The most stable isotope is nobelium-259 that has a half-life of fifty-eight minutes. The most commonly used isotope is nobelium-255 has a half-life of 3.1 minutes. Most of the isotopes of nobelium undergo decay through emission of alpha particles. Nobelium-262 is produced in the decay chain of lawrencium-262, while all other isotopes of nobelium are produced by bombarding members of actinide series with carbon-12.
REFERENCES
[1]. Barber, Robert C.; Greenwood, Norman N.; Hrynkiewicz, Andrzej Z.; Jeannin, Yves P.; Lefort, Marc; Sakai, Mitsuo; Úlehla, Ivan M.; Wapstra, Aaldert Hendrik; Wilkinson, Denys H. (1993). “Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements”. Pure and Applied Chemistry. 65 (8): 1757. doi:10.1351/pac199365081757. (Note: for Part I see Pure and Applied Chemistry, vol. 63, no. 6, pp. 879–886, 1991)
[2]. Emsley, John (2011). Nature’s Building Blocks: An A-Z Guide to the Elements. Oxford University Press. pp. 368–9. ISBN 978-0-19-960563-7.
[3]. Silva, pp. 1639
[4]. Silva, pp. 1637–8