Nobelium

ACTINOID · GROUP None · PERIOD 7
102
No
Nobelium
259

Atomic Data

Atomic Number102
SymbolNo
Atomic Weight259 u
Density (STP)N/A
Melting Point826.85 °C (1100 K)
Boiling PointN/A °C (None K)
Electronegativity1.3 (Pauling)
Electron Config.1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 7s2
Oxidation States+2, +3
Phase at STPSolid
CategoryActinoid
Period / Group7 / None
CAS Number10028-14-5

Electron Configuration

[Rn] 5f14 7s2

Shell n Subshell Electrons Cumulative
K11s22
L22s24
L22p610
M33s212
M33p618
M33d1028
N44s230
N44p636
N44d1046
N44f1460
O55s262
O55p668
O55d1078
O55f1492
P66s294
P66p6100
Q77s2102
Total 102 102

Isotopes of Nobelium

Nobelium is monoisotopic: ²⁵⁹No is its only naturally occurring stable isotope, accounting for 100% of all natural Nobelium.

Isotope Symbol Protons Neutrons Abundance Stability
Nobelium-259²⁵⁹No102157traceStable

Abundance & Occurrence

Nobelium is present in Earth's crust at approximately trace amounts by mass and at approximately trace amounts by mass throughout the universe.

Earth's Crust (ppm by mass)

Nobelium
None ppm
Silicon (ref.)
277,000 ppm
Oxygen (ref.)
461,000 ppm

Universe (ppm by mass)

Nobelium
None ppm
Helium (ref.)
230,000 ppm
Hydrogen (ref.)
739,000 ppm

Discovery & History

1957
Nobel Institute (Stockholm): A Swedish-American team at the Nobel Institute reported synthesis of element 102 and proposed the name nobelium: but the results could not be replicated and were later withdrawn, making it a disputed claim.
1966
Georgy Flerov et al. (Dubna): Soviet scientists at the Joint Institute for Nuclear Research in Dubna produced nobelium unambiguously by bombarding uranium with neon ions, confirming its properties; their work eventually established priority, though the name nobelium was retained.
1967
IUPAC: IUPAC formally accepted the name nobelium in honour of Alfred Nobel and the Nobel Prize: despite the irony that the element's synthesis was primarily confirmed by a Soviet team, not the Stockholm group that first proposed the name.

Read more about the discovery of the periodic table of elements →

Safety & Handling

  • Alpha radiation: Nobelium isotopes are alpha emitters with short half-lives (No-259, t½ = 58 min is the longest-lived); they are produced only in atom-counting experiments at heavy ion accelerators.
  • No practical chemical hazard: Nobelium is never produced in quantities sufficient to pose a conventional chemical or bulk radiological hazard; the primary concern is contamination of accelerator targets and recoil catchers.
  • Facility radiation environment: The accelerator facilities required to produce nobelium generate significant prompt radiation (gamma, neutron) during bombardment; personnel safety is managed through shielding and controlled-area access.
  • Regulatory controls: All superheavy element research facilities operate under national nuclear regulatory authority licences with full radiation protection programmes.

Real-World Uses

  • Nuclear physics research: Nobelium isotopes (No-253 to No-259) are produced atom-by-atom at accelerators to study the nuclear shell structure near the predicted doubly-magic nucleus at Z=114, N=184, and to measure decay energies that constrain nuclear models.
  • Relativistic chemistry studies: Nobelium chemistry experiments (centrifuge or gas-phase studies on single atoms) probe whether the divalent No²⁺ state dominates as predicted by relativistic quantum calculations, testing the extension of chemical periodicity to the heaviest elements.
  • No commercial applications: Nobelium is produced in quantities of atoms per experiment; its properties are of purely scientific interest and no practical applications exist or are possible at this scale.

Downloadable Resources

Free periodic table reference sheets for classrooms, study sessions, and laboratory use.

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Frequently Asked Questions

What is nobelium used for?

Nobelium has no practical applications. It is produced only a few atoms at a time in particle accelerators and is used exclusively for fundamental scientific research into the chemistry and nuclear structure of the heaviest elements. Its short-lived isotopes (the longest-lived, No-259, has a half-life of 58 minutes) make any accumulation of macroscopic quantities impossible.

How was nobelium discovered?

The discovery of nobelium was disputed. A Swedish team at the Nobel Institute claimed discovery in 1957 using a different method, but could not reproduce their results. The element was definitively synthesised in 1958 by Albert Ghiorso, Torbjørn Sikkeland, John Walton, and Glenn Seaborg at Berkeley, bombarding curium with carbon ions. Despite the controversy, the name nobelium (after Alfred Nobel) was eventually adopted by IUPAC.

Is nobelium radioactive?

Yes, all isotopes of nobelium are radioactive. The most stable is No-259 with a half-life of 58 minutes; most others decay in seconds to minutes. Nobelium is distinguished chemically from the lighter actinides because it preferentially forms No2+ ions rather than the trivalent 3+ ions typical of actinides, hinting at the relativistic stabilisation of its outer electron configuration.

How did the naming controversy over nobelium arise?

In 1957, researchers at the Nobel Institute in Stockholm announced the synthesis of element 102 and proposed the name nobelium. However, their results could not be independently reproduced by teams in Berkeley or the USSR (Dubna). Berkeley subsequently synthesised the element in 1958 and the Dubna team confirmed synthesis later. Despite Berkeley having more solid experimental evidence, IUPAC eventually assigned the Nobel Institute's proposed name, nobelium, as a compromise, even though the original Swedish claim was considered invalid.