SELENIUM

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The origin of this element came from the Greek word "sèlènè" which means moon.

Selenium was discovered in 1817 by two men that go by Johan Gottlieb Gahn and Jöns Jacob Berceius.

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• Atomic Number- 34
• Atomic Mass- 78.96
• Atomic Size- 120pm

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• State of matter- Solid
• Density- 4.79g
• Conductivity- amorphous
• Electronegativity: 2.55

Specific Heat: 0.32J/gK
Flammability class: combustible solid
Electron Configuration: [Ar] 3d10 4s2 4p4

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• Boiling Point- 685 degrees celcius
• Melting Point- 221 degrees celcius
• Group- 16 Period- 4
• Number of neutrons- 45

SOURCES
Obtained as a by-product of lead, copper and nickel refining. World wide annual production is around 600 tons. Primary mining areas are Canada, USA, Bolivia and Russia.

USES
Photoelectric cells, TV cameras, as a semiconductor in solar batteries, light meters, copy machines, anti-dandruff shampoo and rectifiers. Also colors glass red.

2,8,18,6

IN ITS NATURAL FORM

Additional Notes and friendly reminder: A dose of selenium as small as 5 mg per day can be lethal for many humans.