Emmett

Astatine Essay

Division 3X

April 30,2019 Astatine

Astatine is a non- that only small amounts have ever been produced. The atomic symbol for Astatine is At, has an of 85, and an atomic mass of

210 amu. Because so little of this particular element has been created, not much is known about its physical characteristics. However, we do know that it contains 85 and 125 . Astatine is a very toxic element due to its radioactivity.

Astatine has a of 302.0 °C and a of 337.0 °C. Because of the miniscule amount of astatine ever produced, there are no known uses of the element outside of research.

The discovery of Astatine has had a long and complex history. In 1869,

Mendeleev created his first . He noticed that there was a space directly under , and he needed to figure out what that element was since it had not been discovered yet. In 1940, a of chemists from the University of California Berklee.

Using a , a form of particle accelerator created by Ernest O. Lawrence, the group bombarded the element -209 with Alpha particles. By doing this, the scientists created the first physical example of Astatine. Because of its lack of stability and radioactivity, Astatine only has a half life of 8 hours. In the mid 1940’s, scientists Berta Karlik and Traude Bernet were able to find examples of Astatine in as a result of studying . It was discovered that Astatine appears naturally in both and minerals. Despite this, very little is still known about the element, as only 25 grams of Astatine exists naturally on the planet.

Because Astatine is a and a , scientists predict that Astatine performs similar to other , and is predicted to form salt when reacting with . The common bond of Astatine is Xenon, a that is found in the Earth's

Atmosphere.

Astatine has come up a lot in modern times due to medical scientists predicting that Astatine could be used as a form of treatment for patients. One of the strands of Astatine known as Astatine-209, has enough radioactivity to destroy cells when decayed. Francois Guerard, a chemist who works in Nuclear cancer treatments, wrote in an article on the uses of the element, saying: “Using radioactive to eradicate tumors is nothing new: therapies relying on this approach already exist.

However, available treatments involve the use of radioactive elements, which emit

“beta” particles that penetrate a few millimeters into biological tissues. Although they can be helpful for the treatment of large-sized tumors (several millimeters in diameter), these particles have proved ineffective when targeting those smaller than a millimeter, as they also destroy the healthy tissue around the tumor. On the other hand, astatine-211 emits “alpha” particles whose low penetration into matter (the thickness of a sheet of paper, or just 3 to 4 cells), could make it possible to treat isolated cancer cells

(for example, in the case of leukemia) or small tumors such as disseminated micrometastases, and supplement conventional therapies (chemotherapy or surgery) after which undetectable tumor residues may persist and lead to a recurrence.”

Electron Configuration: [Xe] 4f 145d 106s 2 6p 5