Element Story - Astatine Edition

Astatine is an element with atomic number 85, belonging to Group 17 of the periodic table, and is a radioactive halogen element. It is known to exist as a dark-colored solid at room temperature, and all of its isotopes are radioactive. In nature, it is produced in extremely small amounts through the radioactive decay of uranium and thorium, but due to its short half-life, the amount present in the Earth's crust is very low. Astatine was first artificially created in 1940 and is one of the rarest elements found in nature. Its chemical properties are similar to iodine in the same group, but as the atomic number increases, metallic character tends to increase, so astatine exhibits properties closer to metals among halogens. The radioactive isotope Astatine-211 emits alpha particles and has a half-life of about 7.2 hours, making it a candidate substance for targeted alpha therapy, which selectively attacks cancer cells. It can also be produced in space through the radioactive decay of heavy elements, but due to its short lifespan, it is difficult for large amounts to accumulate in celestial bodies.