[ATOM]

Selenium

 [ATOM]
Information valid for Se-79 unless otherwise noted

Basic Information


Symbol: Se
Atomic Number: 34
Mass: 78.96
Melting Point: 217.0 C
Boiling Point: 684.9 C
Number of Protons/Electrons: 34
Number of Neutrons: 45
Classification: Non-metal
Crystal Structure: Hexagonal
Density @ 293 K: 4.79 g/cm3
Color: gray

Atomic Structure

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

  1. 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