Astatine is a rare and radioactive element found on the periodic table, represented by the symbol At. It is classified as a halogen, which means it shares some properties with elements like fluorine and chlorine. Astatine is extremely scarce in nature, with only a few grams estimated to exist in the Earth's crust at any given time. Its most stable isotope has a very short half-life, making it difficult to study. Due to its radioactivity, astatine has limited practical applications, but scientists are exploring its potential in medical treatments, particularly in targeted alpha-particle therapy for cancer. Understanding astatine can help researchers learn more about the behavior of heavy elements and their interactions in various environments.