Selenium

Selenium
Properties
Atomic symbol	Se
Atomic number	34
Classification	Non-metal
Atomic mass	79.0 amu
Other Information
Date of discovery	1817
Name of discoverer	Jöns Berzelius
Name origin	From the Greek word Selênê (Moon)
Uses	Photoelectric cells, TV cameras
Obtained from	Refining of lead, copper, nickel

Selenium(si-LEE-nee-em) is a conductive non-metal. It is primarily useful in electronic devices, especially in light-sensitive devices.

History

Selenium was discovered by a Swedish chemist named Jöns Jacob Berzelius, in 1817.

Additional Properties

Melting Point: 428.9 °F (220.5 °C or 493.65 K)

Boiling Point: 1265 °F (685 °C or 958 K)

Density: 4.809 grams per cubic centimeter

State of Matter at Room Temperature: Solid

Color: gray

Uses

Selenium's electrical resistance is greatly affected by the amount of light shining on it. Bright light causes it to conduct better, while darkness reduces conductivity. This special property has made selenium useful in devices that respond to the intensity of light, such as electric eyes, photo cells, light meters for cameras and copiers. It is also is able to generate energy in direct sunlight. For this reason, it is a vital ingredient of solar cells. Selenium is also useful in converting alternating current to direct current, which is why it is used in rectifiers.

External links

• https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional
• http://www.chemicalelements.com/elements/se.html