About

Oganesson is the element with the highest atomic number and atomic mass ever synthesized. It is named after Yuri Oganessian for his pioneering research in super-heavy elements. Though located in group 18 with the noble gases, due to extreme relativistic effects, it is predicted to be chemically reactive and a solid semiconductor at room temperature, challenging the definition of its group.

Atomic Properties

Atomic Number118

Atomic Weight294 u

Neutrons (common)176

Electron Configuration[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶

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

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

Electron Affinity5.4 kJ/mol

Oxidation States-1, 0, +1, +2, +4, +6

Covalent Radius157 pm

Periodic Table Position

Group18

Period7

BlockP

Chemical SeriesNoble gases

Physical Properties

State at STPsolid

Crystal Structurebcc

Magnetic Orderingdiamagnetic

Thermal Properties

Melting Point325 K

Boiling Point450 K

Heat of Fusion23.5 kJ/mol

Heat of Vaporization19.4 kJ/mol

Discovery

Discovered byJoint Institute for Nuclear Research, Lawrence Livermore National Laboratory

Discovery Year2,006

Occurrencesynthetic

CAS Number54144-19-3

Electron Configuration

Energy

↿⇂

1s

↿⇂

2s

↿⇂

2p

↿⇂

3s

↿⇂

3p

↿⇂

4s

↿⇂

3d

↿⇂

4p

↿⇂

5s

↿⇂

4d

↿⇂

5p

↿⇂

6s

↿⇂

4f

↿⇂

5d

↿⇂

6p

↿⇂

7s

↿⇂

5f

↿⇂

6d

↿⇂

7p

Isotopes of Oganesson

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁹⁴Og	294.213920	—	0.7 ms	Alpha Decay