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Periodic Table of Elements

 

02/05/09

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Periodic Table


He

Helium

Atomic Number 2

Atomic Symbol He

Name Helium
  Meaning Named for the Latin word 'helios' meaning the sun; discovered in the solar spectrum

Group Noble gases

Atomic Weight 4.002602

Density, g/cubic cm at STP  0.0001785

Melting Point,  °C None; does not solidify even at absolute zero

Boiling Point,  °C, 1 atm -269

Naturally Occurring Isotopes He-3, He-4

Discoverer Janssen

Year 1868

Ionization Energy, eV 24.5874

Configuration 1s2

Description Colorless, odorless gas at STP

   

 

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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