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Lawrencium

What is Lawrencium

Lawrencium (pronounced as lor-ENS-ee-em) is a synthetic chemical element denoted by the chemical symbol Lr, and belongs to the family of actinides.

It has ten isotopes out of which the longest lived one is lawrencium-262 with a half-life of four hours that decays into nobelium-262 and mendelevium-258, through electron capture and alpha decay/spontaneous fission, respectively [1, 3].

History

Origin of its Name: It is named after the American Nuclear Scientist and Nobel Prize winner, Ernest O. Lawrence [1].

Who Discovered Lawrencium: Several isotopes of the element were produced at the Lawrence Berkeley Laboratory (LBL) [1]. However, Albert Ghiorso, Torbjørn Sikkeland, Almon E. Larsh and Robert M. Latimer are considered to be its discoverers [2].

Lawrencium

When and How was it Discovered

In 1958, at the LBL, a new isotope (named later as isotope-257) was obtained after bombarding curium with nitrogen. In 1960, in an attempt to produce isotope-259 of the same element, californium was bombarded with boron, but no concrete results were achieved. Again in 1961, Ghiorso and his team claimed to synthesize isotope-257 by targeting curium against boron [1, 2].

In 1965, the Joint Institute for Nuclear Research (JINR) at the Soviet Union bombarded americium with oxygen and got isotope-256, and also tried to prove the results of LBL as inaccurate. The LBL then claimed that they had actually produced isotope-258. Finally, the LBL was officially recognized as the discoverer of lawrencium by the International Unions of Pure and Applied Chemistry [1].

Classification and Position of the Element on the Periodic Table [1]

Group Unknown
Period 7
Block f

Properties and Characteristics of Lawrencium [1, 2, 3, 6]

General Properties

Relative atomic mass 262
Atomic mass 262 atomic mass units [1]

Physical Properties

Color/appearance Silver white
Odor Unknown
Malleability Unknown
Ductility Unknown
Melting Point/freezing point 1627°C (2961 °F)
Boiling point Unknown
Density Unknown
State of matter at room temperature (Solid/Liquid/Gas) Solid
Hardness Unknown

Chemical Properties

Flammability Unknown
Oxidation states +3

Atomic Data of Lawrencium [1, 2, 3]

Atomic number 103
Valence electrons 1
Quantum numbers Unknown
– n 6
– ℓ 2
– m -2
– m s +1/2
Electron configuration (noble gas configuration) [Rn] 5f147s27p1
Atomic structure
– Number of electrons 103
– Number of neutrons 159
– Number of protons 103
Radius of atom
– Atomic radius 2.46 Å
– Covalent radius 1.61 Å
Electronegativity Unknown
Ionization energy

(kJmol-1)

1st 2nd 3rd 4th 5th 6th 7th
472.8

Lawrencium Bohr Model

Uses of Lawrencium

The element has no large-scale applications other than basic research work as it does not occur freely in nature [1].

Toxic Effects and Hazards of Lawrencium

As the element does not exist in the earth’s crust, it does not pose any health risks. However, handling it in the laboratory could be a bit harmful since it displays radioactivity [5].

Lawrencium Pictures

Interesting Facts

  • It is the heaviest element in the actinide series [4]
  • At the LBL, only two micrograms of lawrencium were produced even after repeated bombardments [4]

Lawrencium Cost

The radioactive metal is not available outside of laboratory production due to its short half-life.

References

  1. http://www.rsc.org/periodic-table/element/103/lawrencium
  2. https://education.jlab.org/itselemental/ele103.html
  3. https://www.chemicool.com/elements/lawrencium.html
  4. http://www.softschools.com/facts/periodic_table/lawrencium_facts/705/
  5. https://www.webelements.com/lawrencium/biology.html
  6. https://hobart.k12.in.us/ksms/PeriodicTable/lawrencium.htm

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