About

Lawrencium is a synthetic radioactive element and the final member of the actinide series. It is named after Ernest Lawrence, inventor of the cyclotron particle accelerator which was crucial for discovering many synthetic elements. Its chemical properties are difficult to study due to its extremely short half-life (a few hours at most), but it's important for understanding the transition to the transactinide elements.

Atomic Properties

Atomic Number103

Atomic Weight266 u

Neutrons (common)163

Electron Configuration[Rn] 5f¹⁴ 7s² 7p¹

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 7s² 7p¹

Electrons per Shell2, 8, 18, 32, 32, 8, 3

Electronegativity1.3

Electron Affinity-29.58 kJ/mol

Oxidation States+3

Ionic Radius88.1 pm

Periodic Table Position

Group3

Period7

BlockD

Chemical SeriesActinoids

Physical Properties

State at STPsolid

Crystal Structurehcp

Thermal Properties

Melting Point1,900 K

Discovery

Discovered byLawrence Berkeley National Laboratory

Discovery Year1,961

Occurrencesynthetic

CAS Number22537-19-5

Electron Configuration

Energy

↿⇂

1s

↿⇂

2s

↿⇂

2p

↿⇂

3s

↿⇂

3p

↿⇂

4s

↿⇂

3d

↿⇂

4p

↿⇂

5s

↿⇂

4d

↿⇂

5p

↿⇂

6s

↿⇂

4f

↿⇂

5d

↿⇂

6p

↿⇂

7s

↿⇂

5f

6d

↿

7p

Isotopes of Lawrencium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁶²Lr	262.109630	—	3.6 h	Electron Capture