Astatine

authors:AWil LMee Table: basic information about and classifications of astatine.|| * [|Name]: Astatine This is the link of a video for astatine: http://periodicvideos.com/links.htm
 * Name:Astatine**
 * Symbol: At**
 * Atomic Number: 85**
 * Atomic Mass: 210**
 * Melting Point: 302 degrees celsius-576 degrees fahrenheit**
 * Boiling Point: 337 dehrees celsius- 639 degrees fahrenheit**
 * Number of Protons/Electrons:85**
 * Number of Neutrons: 125**
 * Classification:**Semi-metallic
 * Color:metallic**
 * [[image:http://www.chemicalelements.com/bohr/b0085.gif width="355" height="353" caption="[Bohr Model of Astatine]"]] ||  ||
 * Number of Energy Levels:** 6
 * First Energy Level:**
 * Second Energy Level:**
 * Third Energy Level:**
 * Fourth Energy Level:**
 * Fifth Energy Level:**
 * Sixth Energy Level:**


 * ** Isotope ** || ** Half Life ** ||
 * At-206 || 29.4 minutes ||
 * At-208 || 1.6 hours ||
 * At-211 || 7.2 hours ||
 * At-215 || 0.1 milliseconds ||
 * At-217 || 32.0 milliseconds ||
 * At-218 || 1.6 seconds ||
 * At-219 || 50.0 seconds ||

History
The existence of "eka-iodine" had been predicted by [|Mendeleev]. Astatine (after [|Greek] αστατος //astatos//, meaning "unstable") was first synthesized in 1940 by [|Dale R. Corson], [|Kenneth Ross MacKenzie], and [|Emilio Segrè] at the [|University of California, Berkeley] by bombarding [|bismuth] with [|alpha particles].[|[][|3][|]] As the [|periodic table of elements] was long known, several scientists tried to find the element following iodine in the halogen group. The unknown substance was called Eka-iodine before its discovery because the name of the element was to be suggested by the discoverer. The claimed discovery in 1931 at the Alabama Polytechnic Institute (now [|Auburn University]) by Fred Allison and associates, led to the spurrious name for the element as //alabamine// (Ab) for a few years.[|[][|4][|]][|[][|5][|]][|[][|6][|]]. This discovery was later shown to be an erroneous one. The name //Dakin// was proposed for this element in 1937 by the chemist Rajendralal De working in [|Dhaka], Pakistan/India.[|[][|7][|]] The name **Helvetium** was chosen by the Swiss chemist Walter Minder, when he announced the discovery of element 85 in 1940, but changed his suggested name to Anglohelvetium in 1942.[|[][|8][|]] It took three years before astatine was found as product of the natural decay processes. The short-lived element was found by the two scientists [|Berta Karlik] and [|Traude Bernert].[|[][|9][|]][|[][|10][|]]