Themes > Science > Chemistry > General Chemistry > Elements > Online Interactive Periodic Table of the Elements > Selenium

Name: Selenium
Symbol: Se
Atomic Number: 34
Atomic Mass: 78.96 amu
Melting Point: 217.0 °C (490.15 °K, 422.6 °F)
Boiling Point: 684.9 °C (958.05005 °K, 1264.8201 °F)
Number of Protons/Electrons: 34
Number of Neutrons: 45
Crystal Structure: Hexagonal
Density @ 293 K: 4.79 g/cm3
Color: gray

Atomic Structure

[Bohr Model of Selenium]  
Number of Energy Levels: 4

    First Energy Level: 2
    Second Energy Level: 8
    Third Energy Level: 18
    Fourth Energy Level: 6

Isotopes

Isotope Half Life
Se-73 7.15 hours
Se-74 Stable
Se-75 119.78 days
Se-76 Stable
Se-77 Stable
Se-78 Stable
Se-79 65000.0 years
Se-80 Stable
Se-82 Stable
 

Facts

Date of Discovery: 1817
Discoverer: Jons Berzelius
Name Origin: From the Greek word Selênê (Moon)
Uses: photoelectric cells, TV cameras
Obtained From: refining of lead, copper, nickel


Information provided by: http://www.chemicalelements.com