Astatine

Statistics:

• Name: Astatine
• Symbol: At
• Classification: Halogen
• Atomic Number: 85
• Atomic Mass: 209.9871 g/mol
• Density: unknown
• Melting: 302°C
• Boiling: 337°C
• Protons & Electrons:85
• Neutrons:125
• Discovered: 1940
• Discovered By: Corson and MacKenzie
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Electrons Per Energy Level:

• Level 1: 2
• Level 2: 8
• Level 3: 18
• Level 4: 32
• Level 5: 18
• Level 6: 7

Isotopes:

Isotope: Half-life

• ²⁰⁶At: 30.0 minutes
• ²⁰⁸At: 1.63 hours
• ²¹¹At: 7.214 hours
• ²¹⁵At: 0.10 milliseconds
• ²¹⁷At: 32.3 milliseconds
• ²¹⁸At: 1.5 seconds
• ²¹⁹At: 56 seconds

Brief Summary

Astatine is a Halogen with the symbol 'At' and contains 85 Protons & Electrons with 125 neutrons in the nucleus of the atom. Astatine has an atomic mass of 209.9871 g/mol . It will melt at a temperature of 302°C and boil at 337°C.

Astatine was discovered by Corson and MacKenzie in 1940 and is named 'Astatine' Greek word "astatos" meaning "unstable".

Some common usages for Astatine: currently unknown.

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

Astatine :: At :: 85 - Chemical Element. 10 Mar. 2010 <http://www.chemicalelement.com/element/astatine.html>.