ElementsWhat is nobelium?
Nobelium is a radioactive element made a few atoms at a time in particle accelerators.
What is nobelium used for?
Research only.
Where the name comes from
In honour of Alfred Nobel.
Key facts
- Symbol
- No
- Atomic number
- 102
- Atomic mass
- 259.10100 u
- Family
- Actinide
- Period
- 7
- Group
- none (f-block)
- Block
- f
- State at room temperature
- Solid
- Melting point
- 826.9 °C (1,100 K, 1,520 °F)
- Boiling point
- not measured
- Density
- not measured
- Electrons per shell
- 2, 8, 18, 32, 32, 8, 2
- Electron configuration
- [Rn]7s2 5f14
- Common oxidation states
- +3, +2
- Electronegativity (Pauling)
- 1.3
- First ionisation energy
- 6.65 eV
- Electron affinity
- no value
- Atomic radius (van der Waals)
- no value
- Discovered
- 1957
Place in the periodic table
Nobelium is element number 102. It sits in period 7 (row 7) of the periodic table, in the separate row of actinides drawn below the main table, and belongs to the f-block. Just before it comes mendelevium (101), and just after it comes lawrencium (103).
Family: Actinides.
Physical properties
At room temperature nobelium is a solid. Its melting point is about 826.9 °C. Its boiling point has not been measured reliably.
Inside the atom
An atom of nobelium has 102 protons in its nucleus and, when neutral, 102 electrons around it. The electrons are arranged in 7 shells: 2, 8, 18, 32, 32, 8, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Rn]7s2 5f14.
Its electronegativity on the Pauling scale is 1.3. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 6.65 electronvolts (about 642 kilojoules per mole). One mole of nobelium weighs 259.10100 grams, so a single gram contains about 2.32 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains nobelium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.