103
Lr
Lawrencium
262
Lawrencium (Lr)
ActinideGroup 3Period 7d-block-blockRadioactive
Lawrencium is a synthetic chemical element with chemical symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series.
Latin name: Lawrencium
Atomic Number
103
Atomic Mass
262 g/mol
Phase (STP)
Solid (predicted)
Electron Config.
[Rn] 5f¹⁴ 7s² 7p¹
General
SymbolLr
Atomic Number103
Atomic Mass262 g/mol
CategoryActinide
Group3
Period7
Blockd-block
Electron Configuration[Rn] 5f¹⁴ 7s² 7p¹
Valence Electrons17
Coloursilvery (predicted)
Physical Properties
Phase (STP)Solid (predicted)
Density15.6 (predicted)
Melting Point1900 (predicted)
Boiling Point4000 (predicted)
Atomic Properties
Atomic Radius246 pm
Electronegativity1.3 Pauling
Oxidation States+3
Ion ChargeLr3+
Nuclear & Hazards
RadioactiveYes
Half-life3.6 hours (Lr-262)
Abundance
In Earth's Crust0%
Discovery & History
Discovery Year1961
Discovered ByLawrence Berkeley National Laboratory
Country of DiscoveryUSA
Isotopes of Lawrencium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Lr-262 | — | 3.6 hours | SF, α |
| Lr-266 | — | 11 hours | SF |