According to Chemicool, the element astatine was first produced by Dale R. Coson, Kenneth Ross Mackenzie and Emilio Segrè in 1940. Berta Karlik and Traude Bernert found astatine in nature three years later, according to Chemicool.Know More
Web Elements explains that scientists can produce astatine by bombarding bismuth-209 with alpha particles. Astatine's symbol is "At," its atomic weight is 210 and its atomic number is 85. Astatine-210 is the longest-lived isotope with a half-life of 8.3 hours, according to Web Elements.
Per Chemicool, astatine-211 is useful as a radioactive tracer and in some cancer treatments. It is a radioactive halogen and accumulates in the thyroid in a manner similar to iodine.Learn more in Chemistry
Oxygen was discovered in 1772 by Carl Wilhelm Scheele, who wrote a paper with his findings in 1775, which was published in 1777. In 1774, Joseph Priestley independently discovered oxygen and published his findings in 1775.Full Answer >
Oxygen was discovered independently by Joseph Priestley in England and Carl Scheele in Sweden. The existence of such a gas as oxygen had been theorized as long ago as the time of Leonardo da Vinci. Others had isolated oxygen before Priestly and Scheele but didn't recognize it.Full Answer >
Ernest Rutherford gets credit for the discovery of the proton. While conducting the first experiment in splitting the atom between nitrogen and alpha particles, he discovered what had been hypothesized for many years before: the proton.Full Answer >
Oxygen was first discovered in England by Joseph Priestley in 1774. Up until this time, it was commonly believed that air was one single substance. Priestley correctly identified that air was composed of multiple elements, including oxygen.Full Answer >