Nobelium (No)
Nobelium (symbol No) is the chemical element with atomic number 102: an actinide, solid at 0 °C, radioactive, made artificially, with an atomic mass of 259 u. Discovered in 1966 (Georgy Flerov et al. (Dubna)).
Nobelium, named after Alfred Nobel, inventor of dynamite and founder of the Nobel Prizes, is a synthetic element made atom by atom. Its discovery was claimed by three laboratories (Stockholm, Berkeley, Dubna) and sparked decades of controversy. Its most stable isotope, nobelium-259, has a half-life of about an hour. It is known to behave chemically in an unusual way for an actinide.
Key facts
- Atomic number
- 102
- Symbol
- No
- French name
- Nobélium
- Atomic mass
- 259 u
- Molar mass
- [259] g/mol
- Family
- Actinides
- Position
- period 7, f-block
- State at 0 °C
- Solid
- Melting point
- 826.9 °C
- Electronegativity (Pauling)
- 1.3
- First ionization energy
- 642 kJ/mol
- Electron configuration
- [Rn] 5f¹⁴ 7s²
- Radioactive
- yes
- Discovery
- 1966, Georgy Flerov et al. (Dubna)
Origin of the name
In honor of Alfred Nobel.
What does nobelium look like?
Never observed in visible amounts; presumed to be a silvery metal.
Where is nobelium found?
Absent from nature.
How is nobelium produced?
A curium target is bombarded with a beam of carbon nuclei in a particle accelerator. When a carbon nucleus fuses with a curium nucleus, an atom of nobelium forms, detected by its decay.
Top producers
- Russia (Dubna)
- United States (Berkeley)
- Germany (GSI)
What is nobelium used for?
- Basic research only
- Precision laser measurements of the structure of heavy nuclei
In everyday life
- None — it exists only for moments in the lab
Role in living things
No biological role.
Hazards of nobelium
Radioactive, but produced atom by atom: no practical danger.
Cosmic origin
- Human-made: Does not exist (or barely) in nature: synthesized in a reactor or accelerator.
History of nobelium
In 1957, a team at the Nobel Institute in Stockholm announced element 102 and proposed the name nobelium, but no one could reproduce its results. Berkeley claimed the discovery in 1958, also disputed. In the end, Georgy Flerov's experiments in Dubna, USSR, carried out between 1963 and 1966, were recognized as conclusive. The Swedish name, already in common use, was kept nonetheless.
Did you know?
- Unlike most actinides, which prefer to lose three electrons, nobelium is most stable in a form that has lost only two.
- In 2016, GSI physicists used laser spectroscopy to measure an energy level of a nobelium atom for the first time, a feat for such a heavy element.
- It was one of the elements at the heart of the “Transfermium Wars,” the US–Soviet dispute over who discovered what first.
Isotopes of nobelium
No stable isotopes; nobelium is produced only a few atoms at a time, in particle accelerators.
- nobelium-254: radioactive, half-life 51 s. The isotope whose identification, in 1966 in Dubna, established the element's discovery.
- nobelium-259: radioactive, half-life 58 min. The longest-lived.
Related elements
Same family (actinides): Actinium (Ac), Thorium (Th), Protactinium (Pa), Uranium (U), Neptunium (Np), Plutonium (Pu), Americium (Am), Curium (Cm), Berkelium (Bk), Californium (Cf), Einsteinium (Es), Fermium (Fm), Mendelevium (Md), Lawrencium (Lr).