- published: 25 May 2009
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Lawrencium ( /ləˈrɛnsiəm/ lə-REN-see-əm) is a radioactive synthetic chemical element with the symbol Lr (formerly Lw) and atomic number 103. In the periodic table of the elements, it is a period 7 d-block element and the last element of the actinide series. Chemistry experiments have confirmed that lawrencium behaves as the heavier homologue to lutetium and is chemically similar to other actinides.
Lawrencium was first synthesized by the nuclear-physics team led by Albert Ghiorso on February 14, 1961, at the Lawrence Berkeley National Laboratory of the University of California. The first atoms of lawrencium were produced by bombarding a three-milligram target consisting of three isotopes of the element californium with boron-10 and boron-11 nuclei from the Heavy Ion Linear Accelerator. The team suggested the name lawrencium, and the symbol "Lw", but IUPAC changed the symbol to "Lr" in 1963. It was the last element of the actinide series to be produced.
All isotopes of lawrencium are radioactive; its most stable known isotope is lawrencium-262, with a half-life of approximately 3.6 hours. All its isotopes except for lawrencium-260, -261 and -262 decay with a half-life of less than a minute.
Demetria Devonne "Demi" Lovato (born August 20, 1992) is an American singer-songwriter, musician, and actress. Her earliest roles included Angela on Barney & Friends, before she became better known for her starring roles in the Camp Rock movies, as Sonny Munroe in the Disney sitcom Sonny with a Chance, and as the star of the 2009 movie Princess Protection Program. She is also involved in philanthropic activities through charity work and various social and environmental causes.
As a solo musical artist, Lovato released her debut album Don't Forget on September 23, 2008. The album debuted at number two on the Billboard 200 selling 89,000 copies in the first week. It has since shipped over 500,000 copies, earning a gold certification in the United States. Lovato released her second album, Here We Go Again, on July 21, 2009. The album debuted at number one on the Billboard 200, selling 108,000 copies in the first week. Her third studio album, Unbroken, was released on September 20, 2011 and peaked at number four on the Billboard 200. She is working on her fourth studio album.