Selenium Element in Periodic Table | Atomic Number Atomic Mass


Selenium Element:

Selenium is the chemical in the 16th group and 4th period of the periodic table. It is indicated by the symbol Se and the atomic number of selenium is 34. Se is a non-metal. Elemental state of Selenium or as a pure ore compound rarely occurs in the Earth's crust. It contains seven natural isotopes, including 74Se, 76Se, 77Se, 78Se, 79Se, 80Se, 82Se as well as 23 other synthetic isotopes.

Uses Of Selenium Element:

  • Today the biggest use of selenium is glassmaking.
  • Se is also used to make pigments for ceramics, paint and plastics.
  • Selenium is a semiconductor and is used in photocells, solar cells and photocopiers.
  • It is used in some anti-dandruff shampoos because it is toxic to the scalp fungus that causes dandruff.
  • Se  is also used as an additive to make stainless steel.
  • Selenium is an essential trace element for some species, including humans. Small amount of selenium can cause health problems; but large amount is much dangerous since it is carcinogenic in nature and teratogenic deforming foetal development in humans.


Selenium Element Information:

Discovery year: 1817

Discovered by: Jöns Jakob Berzelius and Johann Gottlieb Gahn

Atomic number: 34

Relative atomic mass: 78.971 

Electron configuration: [Ar] 3d10 4s2 4p4

Block: p-block

Other elements in the same block:

Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Aluminium, Silicon, Phosphorus, Sulfur, Chlorine, Argon, Gallium, Germanium, Arsenic, Bromine, Krypton, Indium, Tin, Antimony, Tellurium, Iodine, Xenon, Thallium, Lead, Bismuth, Polonium, Astatine, Radon, Nihonium, Flerovium, Moscovium, Livermorium, Tennessine and Oganesson are the same block elements.

Period: period 4

Other elements in the same period:

Potassium, Calcium, Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Gallium, Germanium, Arsenic, Bromine and Krypton.

Group: group 16 (chalcogens)

Other elements in the same group:

Oxygen, Sulfur, Tellurium, Polonium and Livermorium are the same group elements.

Other elements in the same orbital:

Gallium, Germanium, Arsenic, Bromine and Krypton are the elements in the same orbital.

Allotropes: none

Key isotopes: 80Se 

Melting point: 220.8°C, 429.4°F, 494 K 

Boiling point: 685°C, 1265°F, 958 K 

Element category:  polyatomic non-metal

Density (g cm−3): 4.809 

CAS number: 7782-49-2

Color: black, red, and gray allotropes

You can know detailed information for each element,

Hydrogen, HeliumLithiumBerylliumBoronCarbonNitrogenOxygenFluorine,  Neon , SodiumMagnesiumAluminiumSiliconPhosphorusSulfurChlorineArgon, PotassiumCalciumScandiumTitaniumVanadiumChromiumManganeseIronCobaltNickelCopperZincGalliumGermaniumArsenicSeleniumBromine, Krypton,  Rubidium, StrontiumYttriumZirconiumNiobiumMolybdenumTechnetiumRutheniumRhodiumPalladiumSilverCadmiumIndiumTinAntimonyTelluriumIodine, Xenon,  Caesium, BariumLanthanum,  CeriumPraseodymiumNeodymiumPromethiumSamariumEuropiumGadoliniumTerbiumDysprosiumHolmiumErbiumThuliumYtterbiumLutetiumHafniumTantalumTungstenRheniumOsmiumIridiumPlatinumGoldMercuryThalliumLeadBismuthPoloniumAstatine, Radon,  Francium, RadiumActiniumThoriumProtactiniumUraniumNeptuniumPlutoniumAmericiumCuriumBerkeliumCaliforniumEinsteiniumFermiumMendeleviumNobeliumLawrenciumRutherfordiumDubniumSeaborgiumBohriumHassiumMeitneriumDarmstadtiumRoentgeniumCoperniciumNihoniumFleroviumMoscoviumLivermoriumTennessine, Oganesson.

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