Selenium

Statistics:

• Name: Selenium
• Symbol: Se
• Classification: Non-Metal
• Atomic Number: 34
• Atomic Mass: 78.96 g/mol
• Density: 4.82 g/cm³
• Melting: 217°C
• Boiling: 685°C
• Protons & Electrons:34
• Neutrons:45
• Discovered: 1817
• Discovered By: Berzelius
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Electrons Per Energy Level:

• Level 1: 2
• Level 2: 8
• Level 3: 18
• Level 4: 6

Isotopes:

Isotope: Half-life

• ⁷³Se: 7.15 hours
• ⁷⁴Se: stable
• ⁷⁵Se: 119.779 days
• ⁷⁶Se: stable
• ⁷⁷Se: stable
• ⁷⁸Se: stable
• ⁷⁹Se: 1.13e+6 years
• ⁸⁰Se: stable
• ⁸²Se: 1.08e+20 years

Brief Summary

Selenium is a Non-Metal with the symbol 'Se' and contains 34 Protons & Electrons with 45 neutrons in the nucleus of the atom. Selenium has an atomic mass of 78.96 g/mol and, at a temperature of 20°C, has a density of 4.82 g/cm³. It will melt at a temperature of 217°C and boil at 685°C.

Selenium was discovered by Berzelius in 1817 and is named 'Selenium' Greek word "Selênê" meaing "Moon".

Some common usages for Selenium: photoelectric cells and TV cameras.

Definitions and Notes

Density listed is at a temperature of 20°C.

Isotopes are forms of an element who have the same atomic number but different mass because they contain different number of neutrons.

Half-life is the time required for a quantity of a subject to fall to half of its current quantity.

MLA Citing Format

Selenium :: Se :: 34 - Chemical Element. 10 Mar. 2010 <http://www.chemicalelement.com/element/selenium.html>.