DEFINITION

France located in the seventh period of Group I of the main (A) subgroup of the Periodic Table.

Refers to elements s-families. Metal. Designation - Fr. Serial number - 87. Relative atomic mass - 223.02 amu.

Electronic structure of the francium atom

The francium atom consists of a positively charged nucleus (+87), inside of which there are 87 protons and 136 neutrons, and 87 electrons move around in seven orbits.

Fig.1. Schematic structure of the francium atom.

The distribution of electrons among orbitals is as follows:

87Fr) 2) 8) 18) 32) 32) 8) 1 ;

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4f 14 5s 2 5p 6 5d 10 6s 2 6p 6 7s 1 .

The outer electronic level of the francium atom contains 1 electron, which is a valence electron (located on the 7s sublevel). The energy diagram of the ground state takes the following form:

The presence of one unpaired electron in the francium atom indicates its ability to exhibit the +1 oxidation state.

The valence electron of a francium atom can be characterized by a set of four quantum numbers: n(main quantum), l(orbital), m l(magnetic) and s(spin):

Examples of problem solving

EXAMPLE 1

- (Francium), Fr, radioactive chemical element of group I of the periodic table, atomic number 87; alkali metal. France was discovered by the French radiochemist M. Peret in 1939... Modern encyclopedia

- (lat. Francium) Fr, chemical element of group I of the periodic system of Mendeleev, atomic number 87, atomic mass 223.0197, belongs to the alkali metals. The isotope 223Fr is radioactive and the most stable (half-life 21.8 min). Named after... Big Encyclopedic Dictionary

- (symbol Fr), a radioactive, metal element of the first group of the periodic table, discovered in 1939. The heaviest element of the ALKALI METALS series. It is present in its natural form in uranium ore, a decomposition product of ACTINIUM. Rare element... ... Scientific and technical encyclopedic dictionary

Fr (named in honor of France, the homeland of M. Pepe, who discovered the element; lat. Francium * a. francium; n. Franzium; f. francium; i. francio, francium), radioactive chemical. element of group I of the Mendeleev system; at. n. 87. Has no stable isotopes.… … Geological encyclopedia

- (lat. Francium), Fr, radioact. chem. element of the 1st group is periodic. systems of elements, at. number 87, refers to alkali metals. Name the most stable of all radioacts. elements found in nature. Natural phosphorus consists of b radioactive 223Fr... ... Physical encyclopedia

Noun, number of synonyms: 2 metal (86) element (159) ASIS Dictionary of Synonyms. V.N. Trishin. 2013… Synonym dictionary

I; Wed [lat. Francium] Chemical element (Fr), radioactive alkali metal. ◁ French, oh, oh. * * * francium (lat. Francium), a chemical element of group I of the periodic table, belongs to the alkali metals. Radioactive, most stable... ... encyclopedic Dictionary

- (lat. Francium), chemical. element I gr. periodic systems, refers to alkali metals. Radioactive, max. The nuclide 223Fr is stable (half-life 22 min). Name from France, the homeland of M. Perey, who discovered the element. One of the rarest and least... Natural science. encyclopedic Dictionary

France- See France (Fr) ... Encyclopedic Dictionary of Metallurgy

France- francis statusas T sritis chemija apibrėžtis Cheminis elementas. simbolis(iai) Fr atitikmenys: lot. francium engl. francium rus. France... Chemijos terminų aiškinamasis žodynas

Books

• Radioactive metals francium and dubnium. Methods for predicting physical parameters, Nikolaev O.S.. The book provides methods for predicting the physical parameters of france and dubnium. These are radioactive metals of the seventh period of D.I. Mendeleev’s table. The short half-lives of these metals...
• De Gaulle and the Gaullists. "Constable" and his associates, Vladlen Maksimov. The book tells about the most famous Frenchman of the 20th century, the founder and first president of the Fifth Republic, from an unusual and unexpected critical side for the Russian reader. The author details...

Francium is an element with atomic number 87. The atomic mass of the longest-lived isotope is 223. Francium is a radioactive alkali metal and has extremely pronounced chemical reactivity.

History of the discovery of France

The metal was discovered back in 1939 by an employee of the Paris Radium Institute named Margarita Perey. She, apparently out of patriotic feelings, named the element in honor of her Motherland. Francium was discovered during the study of the artificially produced element “actinium”: an uncharacteristic radioactive glow was noticed. To be fair, it should be noted that other researchers could have worked on the creation of this element at the same time, but, as they say, the winners are not judged.

Main characteristics

Today, francium is one of the rarest metals (and chemical elements in general) found in nature.

According to scientists' calculations, the content of this metal in the earth's crust is about 340 grams (only astatine contains less). This is mainly due to his physical instability. Being radioactive, it has a very short period half-life (for the most stable isotope it is 22.3 minutes). The only thing that compensates for its natural content is the fact that francium is an intermediate in the decay of uranium-235 and thorium-232. Thus, all francium found naturally is a product of radioactive decay.

How can I get it?

Let's consider the only way to obtain the most stable isotope, francium. This can be done through the nuclear reaction of gold with oxygen atoms. All other methods (meaning radioactive decay) are impractical, since they produce extremely unstable isotopes that “live” no more than a few minutes. Obviously, you won’t be able to obtain this element, like all its compounds, at home (and there’s no reason to, actually). one can find many experiments with other metals.

What chemical properties does francium exhibit?

The properties of francium are similar to cesium. The relativistic effects of the 6p shell ensure that the bond between francium and oxygen in superoxides (for example, the composition FrO 2) is more covalent relative to the superoxides of other elements of this group. Taking into account the lowest electronegativity of all currently existing francs, it is characterized by pronounced chemical activity. All physical properties of this element are indicated only theoretically, since it is not possible to test them in practice due to the short “life” period of this element (density = 1.87 g/cm³, melting t = 27 °C, boiling t = 677 °C, specific heat melting = 9.385 kJ/kg). All compounds of this element are soluble in water (exceptions: salts perchlorate, chloroplatinate, picrate cobaltinitrite francium). Francium always co-crystallizes with substances that contain cesium. Co-precipitation with insoluble cesium salts (cesium perchlorate or cesium silicotungstate) is observed. Extraction of francium from solutions is carried out:

• cesium and rubidium chloroplatinates Cs 2 PtCl 6 and Rb 2 PtCl 6 ;
• chlorobismuthate Cs 2 BiCl 5 , chlorostanate Cs 2 SnCl 6 and cesium chloroantimonate Cs 2 SbCl 5 2.5H 2 O;
• free heteropolyacids: silicotungstic and phosphotungstic.

What practical significance does this element have?

Despite all its uniqueness, France has not yet been used in practice. Accordingly, it is not used in industry or any technology. The reason for this is its extremely short half-life. There is evidence that francium chloride can be used to diagnose oncological tumors, however, due to the significant cost of this formation, this kind of technique cannot be introduced into systematic use. In principle, cesium has the same properties.

So this property of franc also turned out to be unclaimed: its cost is compared with the cost of a ton of platinum or gold. According to leading experts, the element in question will always have purely cognitive value, nothing more.

- (Francium), Fr, radioactive chemical element of group I of the periodic table, atomic number 87; alkali metal. France was discovered by the French radiochemist M. Peret in 1939... Modern encyclopedia

FRANCE- (lat. Francium) Fr, chemical element of group I of the periodic system of Mendeleev, atomic number 87, atomic mass 223.0197, belongs to the alkali metals. The isotope 223Fr is radioactive and the most stable (half-life 21.8 min). Named after... Big Encyclopedic Dictionary

FRANCE- (symbol Fr), a radioactive, metal element of the first group of the periodic table, discovered in 1939. The heaviest element of the ALKALI METALS series. It is present in its natural form in uranium ore, a decomposition product of ACTINIUM. Rare element... ... Scientific and technical encyclopedic dictionary

France- Fr (named in honor of France, the homeland of M. Pepe, who discovered the element; lat. Francium * a. francium; n. Franzium; f. francium; i. francio, francium), radioactive chemical. element of group I of the Mendeleev system; at. n. 87. Has no stable isotopes.… … Geological encyclopedia

FRANCE- (lat. Francium), Fr, radioact. chem. element of the 1st group is periodic. systems of elements, at. number 87, refers to alkali metals. Name the most stable of all radioacts. elements found in nature. Natural phosphorus consists of b radioactive 223Fr... ... Physical encyclopedia

France- noun, number of synonyms: 2 metal (86) element (159) ASIS Dictionary of Synonyms. V.N. Trishin. 2013… Synonym dictionary

France- I; Wed [lat. Francium] Chemical element (Fr), radioactive alkali metal. ◁ French, oh, oh. * * * francium (lat. Francium), a chemical element of group I of the periodic table, belongs to the alkali metals. Radioactive, most stable... ... encyclopedic Dictionary

FRANCE- (lat. Francium), chemical. element I gr. periodic systems, refers to alkali metals. Radioactive, max. The nuclide 223Fr is stable (half-life 22 min). Name from France, the homeland of M. Perey, who discovered the element. One of the rarest and least... Natural science. encyclopedic Dictionary

France- See France (Fr) ... Encyclopedic Dictionary of Metallurgy

France- francis statusas T sritis chemija apibrėžtis Cheminis elementas. simbolis(iai) Fr atitikmenys: lot. francium engl. francium rus. France... Chemijos terminų aiškinamasis žodynas

Books

• Radioactive metals francium and dubnium. Methods for predicting physical parameters, Nikolaev O.S.. The book provides methods for predicting the physical parameters of france and dubnium. These are radioactive metals of the seventh period of D.I. Mendeleev’s table. Short half-lives of these metals... Buy for 538 UAH (Ukraine only)
• De Gaulle and the Gaullists. "Constable" and his associates, Vladlen Maksimov. The book tells about the most famous Frenchman of the 20th century, the founder and first president of the Fifth Republic, from an unusual and unexpected critical side for the Russian reader. The author details...

In 1939, Marguerite Perey from the Curie Institute in Paris, while purifying an actinium preparation (Ac-227) from various radioactive decay products, discovered b-radiation, which could not belong to any of the isotopes known at that time. When this isotope (half-life 21 minutes) was subjected to chemical research, it turned out that its properties corresponded to those of ec-caesium. This was finally confirmed after the Second World War, and in 1946 Perey proposed to name the new element Francium in honor of her homeland.

Francium is one of the rarest elements. Among the elements constantly existing in the earth's crust, only astatine has a lower content. All natural francium is radiogenic, its radioactive decay is compensated by the simultaneous emergence of new francium atoms as intermediate products of the decay of uranium-235 and thorium-232. The total content of francium in the earth's crust is estimated at 340 grams. Astatine Occurs in nature.

Physical and Chemical properties. Francium is similar in properties to cesium. Always crystallizes with its compounds. Almost all francium compounds are soluble in water. The relativistic effects of the 6p shell make the bond between francium and oxygen in superoxides, for example, the composition FrO 2, more covalent compared to superoxides of other alkali metals. Francium has the lowest electronegativity of any element currently known. Accordingly, francium is also the most chemically active alkali metal. Cesium The relativistic effects of the 6p shell make the bond of francium with oxygen in superoxides, for example, composition FrO 2, more covalent compared to superoxides of other alkali metals. Francium has the lowest electronegativity of any element currently known. Accordingly, francium is also the most chemically active alkali metal.

Application: Francium chloride FrCl has been used to detect cancerous tumors, but due to the extremely high cost, it is unprofitable to use this salt in large-scale developments. Currently, francium and its salts are not yet used due to their short half-life and high radioactivity.