Lawrencium

Harmful effects: Lawrencium is harmful due to its radioactivity. Characteristics: Lawrencium is a synthetic, highly radioactive metal that has only been produced in miniscule amounts. Lawrencium is a trivalent ion in aqueous solution. (2a) Lawrencium metal has not been prepared. (2b) All of its isotopes are short-lived. Its longest lived isotopes is 262Lr with a half-life of 216 minutes Uses of Lawrencium: Lawrencium is of scientific research interest only.
 * Name:** Lawrencium
 * Symbol:** Lr

Radioactive and Artificially Produced Lawrencium was created by four American scientists, Albert Ghiorso, Torbjørn Sikkeland, Almon E. Larsh and Robert M. Latimer, in March, 1961. Working at the Lawrence Radiation Laboratory in Berkeley, California, the scientists placed three micrograms (0.000003 grams) of californium in the target chamber of a device called a linear accelerator. The scientists used the accelerator to bombard the californium with boron ions. Several different isotopes of lawrencium were created and there is some confusion as to which isotope the group actually detected. Today, the Lawrence Radiation Laboratory is known as the Lawrence Berkeley Laboratory. Lawrencium's most stable isotope, lawrencium-262, has a half-life of 3.6 hours. It decays into nobelium-256 through electron capture or decays through spontaneous fission. Since only tiny amounts of lawrencium have ever been produced, there are currently no uses for it outside of basic scientific research.
 * Number of Protons/Electrons:** 103
 * Number of Neutrons:** 159
 * Classification:** Rare Earth
 * Crystal Structure:** Unknown
 * Density @ 293 K:** Unknown
 * Color:** Unknown
 * Atomic Number:** 103
 * Atomic Weight:** 262
 * Melting Point:** 1900 K (1627°C or 2961°F)
 * Boiling Point:** Unknown
 * Density:** Unknown
 * Phase at Room Temperature:** Solid
 * Element Classification:** Metal
 * Period Number:** 7 **Group Number:** 3 **Group Name:** Actinide
 * What's in a name?** Named after the scientist Ernest O. Lawrence.
 * Say what?** Lawrencium is pronounced as **lor-ENS-ee-em**.
 * History and Uses:**
 * Estimated Crustal Abundance:** Not Applicable
 * Estimated Oceanic Abundance:** Not Applicable
 * Number of Stable Isotopes:** 0 (
 * Ionization Energy:** Unknown
 * Oxidation State:** +3

Atomic Structure

 * [[image:http://www.chemicalelements.com/bohr/b0103.gif width="369" height="367"]] ||  || **Number of Energy Levels:** 7
 * First Energy Level:** **Second Energy Level:** **Third Energy Level:** **Fourth Energy Level:** **Fifth Energy Level:** **Sixth Energy Level:** **Seventh Energy Level:** ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Lr-254 || 13.0 seconds ||

Facts

 * Date of Discovery:** 1961 **Discoverer:** Albert Ghiorso **Name Origin:** After Ernest Lawrence **Uses:** No uses known **Obtained From:** Man-made

Electronic structure
Lawrencium is element 103 in the [|periodic table]. It is the first member of the 6d-block; in accordance with the [|Madelung rule], its [|electronic configuration] should be [Rn]7s25f146d1. However, results from quantum mechanical research have suggested that this configuration is incorrect, and is in fact [Rn]7s25f147p1. A direct measurement of this is not possible. Though early calculations gave conflicting results, [|[8]] more recent studies and calculations confirm the suggestion. [|[9]][|[10]] A strict correlation between the [|periodic table blocks] and the [|orbital-shell] configurations for neutral atoms would classify lawrencium as a [|transition metal] because it could be classed as a [|d-block] element. However, lawrencium is classified as an [|actinide element] according to the IUPAC recommendations.

Gaseous phase
The first gaseous-phase studies of lawrencium were reported in 1969 by a [|nuclear physics] team at the [|Flerov] Laboratory of Nuclear Reactions (FLNR) in the [|Soviet Union]. They used the [|nuclear reaction] 243Am+18O to produce lawrencium nuclei, which they then exposed to a stream of [|chlorine] gas, and a volatile chloride product was formed. This product was deduced to be 256LrCl3, and this confirmed that lawrencium is a typical actinide element. [|[12]]

Aqueous phase
The first aqueous-phase studies of lawrencium were reported in 1970 by a nuclear physics team at the Lawrence Berkeley National Laboratory in California. This team used the nuclear reaction 249Cf+11B to produce lawrencium nuclei. They were able to show that lawrencium forms a trivalent ion, similar to those of the other actinide elements, but in contrast with that of [|nobelium]. Further experiments in 1988 confirmed the formation of a trivalent lawrencium(III) ion using anion-exchange chromatography using α-hydroxy//iso//butyrate (α-HIB) complex. Comparison of the elution time with other actinides allowed a determination of 88.6 pico [|meters] for the ionic radius for Lr3+. Attempts to reduce lawrencium in the lawrencium(III) ionization state to lawrencium(I) using the potent reducing agent hydroxylamine hydrochloride were unsuccessful.