![]() According to Elemental Matter, halogen elements, including astatine, share similar properties they are non-metals, have low melting and boiling points, are brittle when solid, are poor conductors of heat and electricity, and are diatomic (their molecules contain two atoms). According to Lenntech, astatine is the heaviest known halogen.There are only about 25 grams of naturally occurring astatine in Earth's crust at any given time, according to Chemicool.Astatine is named after the Greek word 'astatos,' which means unstable, according to the Jefferson Laboratory.Most common isotopes: At-210 (negligible percent of natural abundance), Am-211 (negligible percent of natural abundance).Number of natural isotopes (atoms of the same element with a different number of neutrons): at least 30 radioactive isotopes.Melting point: 576 degrees Fahrenheit (302 degrees Celsius).Density: approximately 4 ounces per cubic inch (approximately 7 grams per cubic cm).Atomic weight (average mass of the atom): 210.Atomic symbol (on the periodic table of elements): At.Atomic number (number of protons in the nucleus): 85.When Karlik and Bernert were made aware of the published results from the group at Berkeley, they still continued to study element 85 and added greatly to the knowledge about the decay chain that forms the element. Berta Karlik and Traude Bernert in 1942 reported the results of their studies, including the proposed name "viennium." However, because of WWII, the news was kept inside the German territories, and science news from other regions of the world was not brought in, so Karlik and Bernert were not aware of similar results from the Berkeley group. Yet another group of researchers independently identified and characterized element 85 in the early 1940s, according to Thornton and Burdette. The element was highly radioactive and unstable, which led to the name astatine from the Greek word that meant "unstable." This reaction created astatine-211 as well as two free neutrons. As no one had been able to find the rare element in nature, this group of scientists artificially produced it by bombarding bismuth-209 with alpha particles in a particle accelerator. Coson, Kenneth Ross Mackenzie and Emilio Segrè, researchers at the University of California Berkeley, according to Chemicool. The first successfully recognized discovery of astatine was in 1940 by Dale R. Unfortunately, the breakout of World War II disrupted their research as well as communications among scientists around the world. They used chemical separation and published that they found three X-ray spectral lines for the element that closely matched previous predictions. Horia Hulubei and Yvetter Cauchois, researchers at the Sorbonne in Paris, published the results of their discovery of element 85 in 1938.
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