My Science School

In Dmitri Mendeleev’s periodic table of the year 1869, there was a space directly under iodine. The name for the element to fill this space was called ‘eka-iodine’ and the scientists began searching for the element that would fill up this space. But even 71 years later, this element could not be discovered in nature and was instead synthesized in the earliest particle accelerator.

Astatine was first produced by Dale R. Coson, Kenneth Ross Mackenzie, and Emilio Segrè at the University of California, Berkeley in 1940. Segrè, who was working with Carlo Perrier, had synthesized technetium in the year 1937. Researchers had found that the isotope they had created was radioactive, so they named this element based on the Greek term ‘astatos’ which means unstable.

Traces of astatine appear in uranium and thorium minerals as a decay product naturally. The element is highly radioactive. Astatine is the rarest naturally occurring element and at any given time, there are only about 25 grams of naturally occurring astatine on our planet.

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In the year 1898, Marie and Pierre Curie made their first elemental discovery and that was polonium. They discovered polonium and then radium in the same year in Paris while studying the radioactivity in pitchblende (uranium oxide). Polonium is named after Poland, where Marie Curie was born and raised.

The Curies were not aware of the dangers of working with radioactive elements when they made their discoveries. Polonium is harmful because of its chemical toxicity and radioactivity. Exposure to polonium puts people at the risk of getting various cancers.

Radium was discovered in 1898 by the Curies. To extract 1 gram of radium, about eight tons of pitchblende which has up to 50 percent uranium is needed. The element radium gets its name from the Latin word ‘radius’ which means ray. This is based on the rays emitted by this radioactive element. Metallic radium was first isolated by Marie Curie and Andre Debierne in 1910 by the electrolysis of pure radium chloride solution.

Radium is highly radioactive and causes cancer.

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