About

Rutherfordium is the first transactinide element and is named after New Zealand physicist Ernest Rutherford. It is a highly radioactive, synthetic element whose properties are predicted to be similar to hafnium, the element above it in the periodic table. Only a few hundred atoms have ever been made, and they decay within minutes, limiting its study to its fundamental nuclear and atomic properties.

Atomic Properties

Atomic Number104

Atomic Weight267 u

Neutrons (common)163

Electron Configuration[Rn] 5f¹⁴ 6d² 7s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d² 7s²

Electrons per Shell2, 8, 18, 32, 32, 10, 2

Oxidation States+4

Covalent Radius150 pm

Ionic Radius79 pm

Periodic Table Position

Group4

Period7

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Crystal Structurehcp

Thermal Properties

Melting Point2,400 K

Boiling Point5,800 K

Specific Heat0.111 J/(g·K)

Molar Heat29.637 J/(mol·K)

Heat of Fusion25.9 kJ/mol

Heat of Vaporization576 kJ/mol

Discovery

Discovered byJoint Institute for Nuclear Research and Lawrence Berkeley National Laboratory

Discovery Year1,964

Occurrencesynthetic

CAS Number53850-36-5

Electron Configuration

Energy

↿⇂

1s

↿⇂

2s

↿⇂

2p

↿⇂

3s

↿⇂

3p

↿⇂

4s

↿⇂

3d

↿⇂

4p

↿⇂

5s

↿⇂

4d

↿⇂

5p

↿⇂

6s

↿⇂

4f

↿⇂

5d

↿⇂

6p

↿⇂

7s

↿⇂

5f

↿

6d

7p

Isotopes of Rutherfordium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁶⁷Rf	267.121790	—	2.5 h	Spontaneous Fission, Alpha Decay