The chemical element of France (Fr 87) is one of the periodic system of Mendeleev's elements. By 1925, it was one of four elements not found. This is the heaviest and most active alkali metal that exists in nature, and it is also the fastest for the half-life of existing chemical elements. This, as well as low nuclear stability, favored the fact that for a long time it was impossible to discover France, the existence of which was predicted by Mendeleev almost a century before its receipt.
History of the discovery of the chemical element france
She is distinguished by the fact that she fell to the fate of a woman whose name is Margarita Pere. The search for this substance was based on the Mendeleev system. On the basis of substances adjacent to No. 87, various hypotheses were put forward about the properties of this metal:
- due to the fact that neighboring cesium melts at room temperature, it was assumed that the 87th element would also melt at low temperatures;
- it was believed that it would relate to such liquid metals as cesium or mercury;
- hypotheses were put forward about its radioactivity.
By the end of 1938, Margarita Pere joined in the search for this substance. She focused on alpha particles emitted by sea anemone. She well cleared this substance from various impurities, leaving only a pure element. After lengthy chemical treatments, a mother liquor containing alkaline salts remained in the scientist's hands. She suggested that it was not radioactive, but after evaporation, beta activity became apparent with a half-life of 22 minutes. It immediately became clear to the woman that this speed depended directly on the action of the alkaline element.
The continued work of Margarita was successful only in the fall of 1939. Based on the existing nomenclature, the woman gave the 87th element the name "Actinium-K", which was later renamed to France in memory of the place in which it was born. The International Union of Theoretical and Applied Chemistry adopted the name coined by Margarita Pere. So the discovery of France took place.
Chemical element Fr: characteristic
This is the heaviest and most active alkali metal that exists in nature, and it is also one of the fastest half-life of the existing chemical elements. The longest-lived of its isotopes can be found in uranium minerals. Therefore, the chemical element of France is very poorly studied, since it decays quickly. Moreover, it has a very high radioactivity. Nevertheless, small quantities of this element were investigated, and the following properties were discovered:
- the half-life of the longest-lived isotope is 22 minutes;
- melting point - 27 degrees;
- density at room temperature 1.87 g / m 3 .
Interesting facts about France
This is the last chemical element discovered in nature. It is one of the rarest, as it is very unstable and quickly decays. According to scientists, the chemical element of France is present on Earth in total 30 grams. It can be attributed to liquid metals, but it is liquid for a short time. After a few seconds, France decays into more stable elements, in particular radium.
France application
But, despite the high instability, this chemical element also benefits. It is used, although not widely. First of all, the chemical element of France is useful for detecting actinium in natural objects. In addition, thanks to experiments with laboratory rats, scientists have found that it accumulates in malignant tumors, which are at the first stage of development. Therefore, it can be used for early diagnosis of sarcoma. But research on this element continues. France reveals to scientists more and more of its secrets.