Nobelium Facts - No Element

Nobelium Basic Facts

Atomic Number: 102

Symbol: No

Atomic Weight: 259.1009

Discovery: 1957 (Sweden) by the Nobel Institute for Physics; April 1958 at Berkeley by A. Ghiorso, T. Sikkeland, J.R. Walton, and G.T. Seaborg

Electron Configuration: [Rn] 7s² 5f¹⁴

Word Origin: Named for Alfred Nobel, discoverer of dynamite and founder of the Nobel Prize.

Isotopes: Ten isotopes of nobelium are recognized. Nobelium-255 has a half-life of 3 minutes. Nobelium-254 has a half-life of 55-s, Nobelium-252 has a half-life of 2.3-s, and Nobelium-257 has a half-life of 23-s.

Sources: Ghiorso and his colleagues used a double-recoil technique. A heavy-ion linear accelerator was used to bombard a thin target of curium (95% Cm-244 and 4.5% Cm-246) with C-12 ions to produce No-102. The reaction proceeded according to the 246Cm(12C, 4n) reaction.

Element Classification: Radioactive Rare Earth Element (Actinide Series)

Nobelium Physical Data

Melting Point (K): 1100

Appearance: Radioactive, synthetic metal.

Atomic Radius (pm): 285

Pauling Negativity Number: 1.3

First Ionizing Energy (kJ/mol): (640)

Oxidation States: 3, 2

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

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