Selenium

Selenium (/sɨˈliːniəm/ sə-LEE-nee-əm) is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium. It rarely occurs in its elemental state in nature, but instead is obtained as a side-product in the refining of other elements. Selenium is found in sulfide ores such as pyrite, where it partially re... More

Electrons per shell:

  • 2,8,18,6

Discovery Date:

  • 1817

Ionization Energy:

  • 9.7524 eV (0.0000097524 MeV )

Also known as:

  • Selenium, Se

Chemical Element

The 34th Element in the Periodic Table

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Arsenic

Arsenic ( /ˈɑrsɨnɪk/ AR-sə-nik) is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many...

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Bromine

Bromine ( /ˈbroʊmiːn/ BROH-meen or /ˈbroʊmɨn/ BROH-min; from Greek: βρῶμος, brómos, meaning "stench (of he-goats)") is a chemical element with the...

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Symbol:

  • Se

Atomic mass:

Mass Uncertainty
  • 78.96 u (1.311E-16 µg )
  • 0.03 u (5E-20 µg )

Electron affinity:

Value Uncertainty
  • 2.02067 eV (0.00000202067 MeV )
  • 0.00002 eV (2E-11 MeV )

Electronegativity (Pauling scale):

  • 2.55

Atomic radius:

  • 115 pm (0.00000453 )

Covalent radius:

  • 1.16 pm (4.57E-8 )

Van der Waals radius:

  • 190 pm (0.00000748 )

Melting Point:

  • 220.85 °C (429.53 °F )

Boiling Point:

  • 684.85 °C (1264.7 °F )

Periodic table block:

Discovering Country:

Electron Configuration:

  • Ar 3d10 4s2 4p4
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Medicine

Active moieties:

Active ingredient of formulation:

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