Nobelium (No)
Actinide · Radioactive · Synthetic
Nobelium, named for Alfred Nobel, was the subject of a decades-long discovery dispute between labs in Sweden, the USA and the USSR. Unusually for an actinide, its most stable chemistry is in the +2 state.
Position on the periodic table
Atomic properties
| Atomic number | 102 |
|---|---|
| Atomic mass | 259 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 |
| Noble gas shorthand | [Rn] 5f14 7s2 |
| Electrons per shell | 2, 8, 18, 32, 32, 8, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +2, +3 |
| Electronegativity (Pauling) | 1.3 |
| Covalent radius (approx.) | Not available |
| First ionization energy | 642 kJ/mol |
| Electron affinity | -223.2 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | Not available |
| Melting point | 826.85 °C (1100 K) |
| Boiling point | Not available |
| Appearance | Not available |
| Radioactive | Yes |
| Origin | Synthetic (lab-made) |
Electron configuration of nobelium
Nobelium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14, usually shortened to [Rn] 5f14 7s2. Its electrons occupy 7 shells (2, 8, 18, 32, 32, 8, 2), placing it in period 7 of the f-block. Explore it interactively in the electron configuration calculator.
Uses of nobelium
- Fundamental research only
Biological role: None.
Occurrence: Entirely synthetic.
History and discovery
Discovered: 1958 — Joint Institute for Nuclear Research. Name origin: Named after Alfred Nobel, founder of the Nobel Prizes.
First convincing synthesis at Dubna (USSR) in the late 1950s–60s; the Swedish Nobel Institute's 1957 claim was not confirmed.
Safety notes
Radioactive; atom-scale research quantities only.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Nobelium
1. What is the chemical symbol of Nobelium?
2. What is the atomic number of Nobelium?
3. Which category does Nobelium belong to?
4. What is the state of Nobelium at room temperature?
5. Which period of the periodic table is Nobelium in?
Nobelium FAQs
What is the atomic number of nobelium?
Nobelium's atomic number is 102 — every nobelium atom has 102 protons in its nucleus.
What is the symbol for nobelium?
No. Named after Alfred Nobel, founder of the Nobel Prizes.
Is nobelium a metal, nonmetal, or metalloid?
Nobelium is classified as a actinide.
What state is nobelium at room temperature?
At about 25 °C, nobelium is a solid. It melts at 826.85 °C.
What is nobelium used for?
Key uses include: fundamental research only.
Related elements
Keep working with this element
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