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Periodic Table of Elements

 

02/05/09

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Periodic Table


Ac

Actinium

Atomic Number 89

Atomic Symbol Ac

Name Actinium
  Meaning Name comes from the Greek word 'akinis' meaning 'ray'

Group Rare earth

Atomic Weight 227

Density, g/cubic cm at STP 10.07

Melting Point, °C 1050

Boiling Point, °C, 1 atm 3200

Naturally Occurring Isotopes Ac-227

Discoverer Debierne/Giesel

Year 1899/1902

Ionization Energy, eV 5.17

Configuration [Rn] 6d 7s2

Description Lustrous metal, first member of the Actinide Series

   

Information
Actinium is an ultra-rare radioactive element found in uranium ores where it forms as a result of unusual nuclear reactions. The longest-lived isotope, Ac-228, has a half-life of 6 hours. It is never isolated in visible amounts.

Joseph's Element Collection
Joseph bought this Torbenite uranium ore mineral from United Nuclear. There will likely be a few atoms of Actinium somewhere in it at any given time. If he had a visible quantity in his collection, he would be dead.

References:

Holden, Norman E. (March 30, 2004). "History of the origin of the chemical elements and their discoverers." National Nuclear Data Center. Retrieved October 7, 2005 from http://www.nndc.bnl.gov/content/elements.html

"List of elements by boiling point." (September 22, 2005). Wikipedia. Retrieved October 9, 2005 from http://en.wikipedia.org/wiki/List_of_elements_by_boiling_point

"List of elements by density." (September 22, 2005). Wikipedia. Retrieved October 9, 2005 from http://en.wikipedia.org/wiki/List_of_elements_by_density

"List of elements by melting point." (September 22, 2005). Wikipedia. Retrieved October 9, 2005 from http://en.wikipedia.org/wiki/List_of_elements_by_melting_point

"NIST chemistry webBook." (2005). National Institute of Standards and Technology. Retrieved October 6, 2005 from http://webbook.nist.gov/chemistry/

Zucker, M.A.; Kishore, A. R.; Sukumar, R.; and Dragoset, R. A. (July 2005). "Elemental data index."  National Institute of Standards and Technology. Retrieved October 7, 2005 from http://physics.nist.gov/PhysRefData/Elements/cover.html

 


 

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