About

Nobelium is a synthetic element named in honor of Alfred Nobel, the inventor of dynamite and founder of the Nobel Prize. Its discovery was complex and claimed by multiple labs over many years. It is a transuranic element whose chemical properties, which can only be studied one atom at a time, are still being explored to understand the behavior of heavy actinides.

Atomic Properties

Atomic Number102

Atomic Weight259 u

Neutrons (common)157

Electron Configuration[Rn] 5f¹⁴ 7s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 7s²

Electrons per Shell2, 8, 18, 32, 32, 8, 2

Electronegativity1.3

Electron Affinity-50 kJ/mol

Oxidation States+3, +2

Ionic Radius110 pm

Periodic Table Position

Group3

Period7

BlockF

Chemical SeriesActinoids

Physical Properties

State at STPsolid

Crystal Structurefcc

Thermal Properties

Melting Point1,100 K

Discovery

Discovered byJoint Institute for Nuclear Research

Discovery Year1,966

Occurrencesynthetic

CAS Number10028-14-5

Electron Configuration

Energy

↿⇂

1s

↿⇂

2s

↿⇂

2p

↿⇂

3s

↿⇂

3p

↿⇂

4s

↿⇂

3d

↿⇂

4p

↿⇂

5s

↿⇂

4d

↿⇂

5p

↿⇂

6s

↿⇂

4f

↿⇂

5d

↿⇂

6p

↿⇂

7s

↿⇂

5f

6d

7p

Isotopes of Nobelium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁵⁹No	259.101030	—	58 m	Alpha Decay, Electron Capture