What Group Is Francium In

Element, symbol Fr and atomic number 87

Francium, ₈₇ Fr

Francium
Pronunciation	​( FRAN-see-əm)
Mass number	[223]
Francium in the periodic tabular array
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Atomic number 26 Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gilt Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Cs ↑ Fr ↓ (Uue) radon ← francium → radium
Diminutive number (Z)	87
Group	group i: hydrogen and brine metals
Period	period 7
Block	south-block
Electron configuration	[Rn] 7s1
Electrons per beat out	2, 8, xviii, 32, 18, 8, 1
Concrete properties
Phase atSTP	solid
Melting betoken	300 M ​(27 °C, ​81 °F)
Boiling betoken	950 Thousand ​(677 °C, ​1251 °F)
Density (nearr.t.)	2.48 g/cm3 (estimated) [1]
Vapor pressure (extrapolated) P (Pa) i 10 100 1 k 10 k 100 chiliad at T (One thousand) 404 454 519 608 738 946
Atomic backdrop
Oxidation states	+1 (a strongly basic oxide)
Electronegativity	Pauling scale: >0.79
Ionization energies	1st: 393 kJ/mol[2]
Covalent radius	260 pm (extrapolated)
Van der Waals radius	348 pm (extrapolated)
Other properties
Natural occurrence	from decay
Crystal structure	​body-centered cubic (bcc) (extrapolated)
Thermal electrical conductivity	15 W/(m⋅K) (extrapolated)
Electrical resistivity	3 µΩ⋅m (calculated)
Magnetic ordering	Paramagnetic
CAS Number	7440-73-5
History
Naming	after France, homeland of the discoverer
Discovery and kickoff isolation	Marguerite Perey (1939)
Main isotopes of francium
Iso­tope Abun­trip the light fantastic toe Half-life (t i/two) Disuse fashion Pro­duct 212Fr syn xx.0 min β+ 212Rn α 208At 221Fr trace 4.eight min α 217At 222Fr syn fourteen.2 min β− 222Ra 223Fr trace 22.00 min β− 223Ra α 219At
Category: Francium view talk edit | references

Francium is a chemical element with the symbol Fr and atomic number 87. It is extremely radioactive; its nigh stable isotope, francium-223 (originally called actinium M afterward the natural decay chain it appears in), has a half-life of only 22 minutes. Information technology is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). The isotopes of francium decay quickly into astatine, radium, and radon. The electronic structure of a francium atom is [Rn] 7s¹, and so the chemical element is classed as an alkali metal.

Bulk francium has never been seen. Because of the general appearance of the other elements in its periodic table cavalcade, it is presumed that francium would appear as a highly reactive metal, if enough could be collected together to be viewed as a bulk solid or liquid. Obtaining such a sample is highly improbable, since the farthermost heat of decay resulting from its curt half-life would immediately vaporize whatsoever viewable quantity of the element.

Francium was discovered past Marguerite Perey in France (from which the chemical element takes its name) in 1939.^[3] Prior to its discovery, it was referred to as eka-caesium or ekacaesium because of its conjectured existence beneath caesium in the periodic table. It was the final element offset discovered in nature, rather than by synthesis.^{[note ane]} Outside the laboratory, francium is extremely rare, with trace amounts found in uranium ores, where the isotope francium-223 (in the family of uranium-235) continually forms and decays. As little as 200–500 k exists at any given time throughout the Earth'due south chaff; aside from francium-223, its other isotopes are entirely synthetic. The largest amount produced in the laboratory was a cluster of more 300,000 atoms.^[4]

Characteristics [edit]

Francium is ane of the virtually unstable of the naturally occurring elements: its longest-lived isotope, francium-223, has a half-life of simply 22 minutes. The but comparable element is astatine, whose most stable natural isotope, astatine-219 (the alpha daughter of francium-223), has a one-half-life of 56 seconds, although synthetic astatine-210 is much longer-lived with a half-life of viii.1 hours.^[five] All isotopes of francium decay into astatine, radium, or radon.^[5] Francium-223 also has a shorter half-life than the longest-lived isotope of each synthetic chemical element up to and including element 105, dubnium.^[6]

Francium is an alkali metal whose chemical backdrop generally resemble those of caesium.^[6] A heavy element with a single valence electron,^[7] it has the highest equivalent weight of whatsoever element.^[vi] Liquid francium—if created—should have a surface tension of 0.05092 N/m at its melting bespeak.^[eight] Francium'due south melting point was estimated to exist around 8.0 °C (46.4 °F);^[i] a value of 27 °C (81 °F) is also often encountered.^{[half dozen]} The melting signal is uncertain because of the chemical element'southward farthermost rarity and radioactivity; a different extrapolation based on Dmitri Mendeleev's method gave xx ± 1.5 °C (68.0 ± 2.7 °F). The estimated boiling signal of 620 °C (1,148 °F) is also uncertain; the estimates 598 °C (i,108 °F) and 677 °C (ane,251 °F), as well as the extrapolation from Mendeleev's method of 640 °C (1,184 °F), have also been suggested.^{[one] [eight]} The density of francium is expected to be around 2.48 g/cm³ (Mendeleev's method extrapolates two.4 thou/cm³).^[1]

Linus Pauling estimated the electronegativity of francium at 0.7 on the Pauling scale, the same as caesium;^[9] the value for caesium has since been refined to 0.79, just there are no experimental information to permit a refinement of the value for francium.^[x] Francium has a slightly higher ionization energy than caesium,^[11] 392.811(4) kJ/mol as opposed to 375.7041(2) kJ/mol for caesium, as would be expected from relativistic effects, and this would imply that caesium is the less electronegative of the two. Francium should too have a college electron affinity than caesium and the Fr⁻ ion should be more polarizable than the Cs⁻ ion.^[12]

Compounds [edit]

Due to francium being very unstable, its salts are only known to a small extent. Francium coprecipitates with several caesium salts, such every bit caesium perchlorate, which results in pocket-size amounts of francium perchlorate. This coprecipitation tin be used to isolate francium, past adapting the radiocaesium coprecipitation method of Lawrence Eastward. Glendenin and C. M. Nelson. It volition additionally coprecipitate with many other caesium salts, including the iodate, the picrate, the tartrate (too rubidium tartrate), the chloroplatinate, and the silicotungstate. Information technology besides coprecipitates with silicotungstic acid, and with perchloric acid, without some other alkali metal as a carrier, which leads to other methods of separation.^{[13] [14]}

Francium perchlorate [edit]

Francium perchlorate is produced by the reaction of francium chloride and sodium perchlorate. The francium perchlorate coprecipitates with caesium perchlorate.^[fourteen] This coprecipitation can be used to isolate francium, by adapting the radiocaesium coprecipitation method of Lawrence E. Glendenin and C. M. Nelson. However, this method is unreliable in separating thallium, which likewise coprecipitates with caesium.^[14] Francium perchlorate's entropy is expected to be 42.7 e.u^[ane] (178.vii J mol^-1 K^-1).

Francium halides [edit]

Francium halides are all soluble in water and are expected to be white solids. They are expected to be produced by the reaction of the corresponding halogens. For example, francium chloride would be produced by the reaction of francium and chlorine. Francium chloride has been studied as a pathway to split francium from other elements, by using the high vapour pressure of the compound, although francium fluoride would have a higher vapour pressure.^[1]

Other compounds [edit]

Francium nitrate, sulfate, hydroxide, carbonate, acetate, and oxalate, are all soluble in water, while the iodate, picrate, tartrate, chloroplatinate, and silicotungstate are insoluble. The insolubility of these compounds are used to extract francium from other radioactive products, such as zirconium, niobium, molybdenum, tin, antimony, the method mentioned in the section to a higher place.^[i] The CsFr molecule is predicted to have francium at the negative stop of the dipole, different all known heterodiatomic brine metal molecules. Francium superoxide (FrO₂) is expected to take a more than covalent graphic symbol than its lighter congeners; this is attributed to the 6p electrons in francium being more involved in the francium–oxygen bonding.^[12]

The only double salt known of francium has the formula Fr₉Bi₂I₉.

Isotopes [edit]

There are 34 known isotopes of francium ranging in atomic mass from 199 to 232.^[xv] Francium has 7 metastable nuclear isomers.^[half-dozen] Francium-223 and francium-221 are the only isotopes that occur in nature, with the former beingness far more common.^[16]

Francium-223 is the nearly stable isotope, with a half-life of 21.8 minutes,^[6] and it is highly unlikely that an isotope of francium with a longer half-life will ever be discovered or synthesized.^[17] Francium-223 is a 5th production of the uranium-235 decay series equally a daughter isotope of actinium-227; thorium-227 is the more common daughter.^[eighteen] Francium-223 then decays into radium-223 by beta decay (one.149 MeV disuse energy), with a minor (0.006%) alpha decay path to astatine-219 (5.iv MeV decay energy).^[19]

Francium-221 has a half-life of iv.viii minutes.^[6] It is the ninth product of the extinct neptunium decay series as a daughter isotope of actinium-225.^[xviii] Francium-221 so decays into astatine-217 by alpha decay (six.457 MeV decay energy).^[6] It is absent in the nowadays Earth, every bit all the members of the chain (excluding ²⁰⁹Bi and ²⁰⁵Tl) had disappeared during first ~twenty My afterward the pre-solar nucleosynthesis event.

The least stable ground country isotope is francium-215, with a half-life of 0.12 μs: it undergoes a 9.54 MeV alpha disuse to astatine-211.^[6] Its metastable isomer, francium-215m, is less stable even so, with a half-life of but 3.5 ns.^[xx]

Applications [edit]

Due to its instability and rarity, there are no commercial applications for francium.^{[21] [22] [23] [18]} Information technology has been used for research purposes in the fields of chemistry^[24] and of atomic construction. Its use every bit a potential diagnostic assistance for various cancers has also been explored,^[5] just this awarding has been deemed impractical.^[22]

Francium'due south ability to be synthesized, trapped, and cooled, along with its relatively simple atomic structure, has fabricated it the subject of specialized spectroscopy experiments. These experiments accept led to more specific data regarding energy levels and the coupling constants betwixt subatomic particles.^[25] Studies on the light emitted past light amplification by stimulated emission of radiation-trapped francium-210 ions accept provided accurate data on transitions between atomic energy levels which are fairly similar to those predicted past quantum theory.^[26]

History [edit]

As early as 1870, chemists thought that in that location should be an alkali metal across caesium, with an atomic number of 87.^[5] It was and then referred to past the provisional name eka-caesium.^[27] Inquiry teams attempted to locate and isolate this missing chemical element, and at to the lowest degree 4 false claims were fabricated that the chemical element had been found before an authentic discovery was made.

Erroneous and incomplete discoveries [edit]

Soviet chemist Dmitry Dobroserdov was the first scientist to claim to have found eka-caesium, or francium. In 1925, he observed weak radioactivity in a sample of potassium, some other alkaline, and incorrectly concluded that eka-caesium was contaminating the sample (the radioactivity from the sample was from the naturally occurring potassium radioisotope, potassium-40).^[28] He and then published a thesis on his predictions of the backdrop of eka-caesium, in which he named the chemical element russium after his home country.^[29] Presently thereafter, Dobroserdov began to focus on his instruction career at the Polytechnic Constitute of Odessa, and he did non pursue the element further.^[28]

The following year, English chemists Gerald J. F. Druce and Frederick H. Loring analyzed X-ray photographs of manganese(II) sulfate.^[29] They observed spectral lines which they presumed to be of eka-caesium. They announced their discovery of element 87 and proposed the name alkalinium, as it would be the heaviest brine metallic.^[28]

In 1930, Fred Allison of the Alabama Polytechnic Plant claimed to have discovered chemical element 87 (in add-on to 85) when analyzing pollucite and lepidolite using his magneto-optical automobile. Allison requested that it exist named virginium afterwards his home country of Virginia, forth with the symbols Vi and Vm.^{[29] [30]} In 1934, H.Thou. MacPherson of UC Berkeley disproved the effectiveness of Allison'due south device and the validity of his discovery.^[31]

In 1936, Romanaian physicist Horia Hulubei and his French colleague Yvette Cauchois also analyzed pollucite, this time using their high-resolution X-ray apparatus.^[28] They observed several weak emission lines, which they presumed to be those of element 87. Hulubei and Cauchois reported their discovery and proposed the name moldavium, along with the symbol Ml, subsequently Moldavia, the Romanian province where Hulubei was built-in.^[29] In 1937, Hulubei'southward work was criticized past American physicist F. H. Hirsh Jr., who rejected Hulubei's inquiry methods. Hirsh was certain that eka-caesium would not be found in nature, and that Hulubei had instead observed mercury or bismuth 10-ray lines. Hulubei insisted that his Ten-ray appliance and methods were too authentic to make such a mistake. Because of this, Jean Baptiste Perrin, Nobel Prize winner and Hulubei'south mentor, endorsed moldavium as the true eka-caesium over Marguerite Perey's recently discovered francium. Perey took pains to exist accurate and detailed in her criticism of Hulubei's work, and finally she was credited as the sole discoverer of chemical element 87.^[28] All other previous purported discoveries of element 87 were ruled out due to francium'due south very express half-life.^[29]

Perey's analysis [edit]

Eka-caesium was discovered on January 7, 1939, by Marguerite Perey of the Curie Found in Paris,^[32] when she purified a sample of actinium-227 which had been reported to have a decay energy of 220 keV. Perey noticed decay particles with an energy level below 80 keV. Perey thought this decay activity might have been caused by a previously unidentified decay production, one which was separated during purification, only emerged again out of the pure actinium-227. Various tests eliminated the possibility of the unknown element existence thorium, radium, lead, bismuth, or thallium. The new product exhibited chemical backdrop of an alkaline (such as coprecipitating with caesium salts), which led Perey to believe that information technology was chemical element 87, produced by the alpha decay of actinium-227.^[27] Perey and so attempted to determine the proportion of beta decay to blastoff decay in actinium-227. Her first test put the alpha branching at 0.half-dozen%, a figure which she later on revised to 1%.^[17]

Perey named the new isotope actinium-Thousand (it is now referred to equally francium-223)^[27] and in 1946, she proposed the name catium (Cm) for her newly discovered chemical element, every bit she believed it to be the most electropositive cation of the elements. Irène Joliot-Curie, i of Perey'due south supervisors, opposed the name due to its connotation of true cat rather than cation; furthermore, the symbol coincided with that which had since been assigned to curium.^[27] Perey then suggested francium, after French republic. This name was officially adopted past the International Spousal relationship of Pure and Applied Chemistry (IUPAC) in 1949,^[5] becoming the second element after gallium to be named subsequently France. It was assigned the symbol Fa, just this abbreviation was revised to the current Fr shortly thereafter.^[33] Francium was the final chemical element discovered in nature, rather than synthesized, following hafnium and rhenium.^[27] Further research into francium's construction was carried out by, amidst others, Sylvain Lieberman and his team at CERN in the 1970s and 1980s.^[34]

Occurrence [edit]

This sample of uraninite contains about 100,000 atoms (3.iii×10 ⁻²⁰  yard) of francium-223 at whatever given time.^[22]

²²³Fr is the result of the blastoff decay of ²²⁷Ac and tin can exist institute in trace amounts in uranium minerals.^[6] In a given sample of uranium, there is estimated to be just 1 francium atom for every one × 10¹⁸ uranium atoms.^[22] It is too calculated that there is a total mass of at most 30 g^[35] or, as other sources propose, 340 to 550 1000 of francium in the Earth'due south chaff at whatsoever given time.^[36]

Product [edit]

A magneto-optical trap, which tin can concord neutral francium atoms for short periods of fourth dimension.^[37]

Francium can be synthesized past a fusion reaction when a gold-197 target is bombarded with a beam of oxygen-18 atoms from a linear accelerator in a process originally adult at the physics department of the Country University of New York at Stony Brook in 1995.^[38] Depending on the energy of the oxygen beam, the reaction tin can yield francium isotopes with masses of 209, 210, and 211.

¹⁹⁷Au + ^xviiiO → ²⁰⁹Fr + 6 n

¹⁹⁷Au + ¹⁸O → ²¹⁰Fr + 5 n

¹⁹⁷Au + ¹⁸O → ²¹¹Fr + 4 n

Image of calorie-free emitted by a sample of 200,000 francium atoms in a magneto-optical trap

Heat paradigm of 300,000 francium atoms in a magneto-optical trap, around 13 nanograms

The francium atoms get out the gold target every bit ions, which are neutralized by standoff with yttrium and then isolated in a magneto-optical trap (MOT) in a gaseous unconsolidated land.^[37] Although the atoms merely remain in the trap for about 30 seconds before escaping or undergoing nuclear decay, the process supplies a continual stream of fresh atoms. The effect is a steady state containing a adequately constant number of atoms for a much longer fourth dimension.^[37] The original apparatus could trap up to a few thousand atoms, while a after improved blueprint could trap over 300,000 at a time.^[4] Sensitive measurements of the light emitted and absorbed past the trapped atoms provided the first experimental results on various transitions between atomic energy levels in francium. Initial measurements bear witness very skillful understanding betwixt experimental values and calculations based on breakthrough theory. The research project using this production method relocated to TRIUMF in 2012, where over ten⁶ francium atoms accept been held at a fourth dimension, including large amounts of ²⁰⁹Fr in add-on to ²⁰⁷Fr and ²²¹Fr.^{[39] [twoscore]}

Other synthesis methods include bombarding radium with neutrons, and bombarding thorium with protons, deuterons, or helium ions.^[17]

²²³Fr can as well be isolated from samples of its parent ²²⁷Ac, the francium existence milked via elution with NH₄Cl–CrO_iii from an actinium-containing cation exchanger and purified by passing the solution through a silicon dioxide compound loaded with barium sulfate.^[41]

In 1996, the Stony Beck group trapped 3000 atoms in their MOT, which was enough for a video photographic camera to capture the light given off past the atoms equally they fluoresce.^[four] Francium has non been synthesized in amounts large enough to counterbalance.^{[v] [22] [42]}

Notes [edit]

1. ^ Some synthetic elements, similar technetium and plutonium, have later been plant in nature.

References [edit]

1. ^ ^{a b c d due east f k} Lavrukhina, Avgusta Konstantinovna; Pozdnyakov, Aleksandr Aleksandrovich (1970). Analytical Chemistry of Technetium, Promethium, Astatine, and Francium. Translated by R. Kondor. Ann Arbor–Humphrey Science Publishers. p. 269. ISBN978-0-250-39923-9.
2. ^ ISOLDE Collaboration, J. Phys. B 23, 3511 (1990) (PDF online)
3. ^ Perey, M. (October one, 1939). "L'élément 87 : AcK, dérivé de l'actinium". Periodical de Physique et le Radium (in French). x (x): 435–438. doi:10.1051/jphysrad:019390010010043500. ISSN 0368-3842.
4. ^ ^{a b c} Orozco, Luis A. (2003). "Francium". Chemical and Engineering News. 81 (36): 159. doi:10.1021/cen-v081n036.p159.
5. ^ ^{a b c d e f} Price, Andy (December xx, 2004). "Francium". Retrieved February nineteen, 2012.
6. ^ ^{a b c d e f g h i j} CRC Handbook of Chemistry and Physics. Vol. 4. CRC. 2006. p. 12. ISBN978-0-8493-0474-3.
7. ^ Winter, Mark. "Electron Configuration". Francium. The University of Sheffield. Retrieved Apr 18, 2007.
8. ^ ^{a b} Kozhitov, L. Five.; Kol'tsov, Five. B.; Kol'tsov, A. Five. (2003). "Evaluation of the Surface Tension of Liquid Francium". Inorganic Materials. 39 (11): 1138–1141. doi:10.1023/A:1027389223381. S2CID 97764887.
9. ^ Pauling, Linus (1960). The Nature of the Chemical Bond (Third ed.). Cornell Academy Printing. p. 93. ISBN978-0-8014-0333-0.
10. ^ Allred, A. L. (1961). "Electronegativity values from thermochemical data". J. Inorg. Nucl. Chem. 17 (3–4): 215–221. doi:ten.1016/0022-1902(61)80142-5.
11. ^ Andreev, S.V.; Letokhov, V.S.; Mishin, V.I. (1987). "Laser resonance photoionization spectroscopy of Rydberg levels in Fr". Physical Review Letters. 59 (12): 1274–76. Bibcode:1987PhRvL..59.1274A. doi:ten.1103/PhysRevLett.59.1274. PMID 10035190.
12. ^ ^{a b} Thayer, John S. (2010). "Chap.10 Relativistic Effects and the Chemistry of the Heavier Main Group Elements". Relativistic Methods for Chemists. Springer. p. 81. doi:10.1007/978-one-4020-9975-5_2. ISBN978-1-4020-9975-five.
13. ^ Hyde, E. K. (1952). "Radiochemical Methods for the Isolation of Element 87 (Francium)". J. Am. Chem. Soc. 74 (xvi): 4181–4184. doi:ten.1021/ja01136a066. hdl:2027/mdp.39015086483156.
14. ^ ^{a b c} Due east. Due north K. Hyde Radiochemistry of Francium, Subcommittee on Radiochemistry, National University of Sciences-National Research Council; available from the Office of Technical Services, Dept. of Commerce, 1960.
15. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics. Vol. eleven. CRC. pp. 180–181. ISBN978-0-8493-0487-3.
16. ^ Considine, Glenn D., ed. (2005). Francium, in Van Nostrand's Encyclopedia of Chemistry. New York: Wiley-Interscience. p. 679. ISBN978-0-471-61525-5.
17. ^ ^{a b c} "Francium". McGraw-Hill Encyclopedia of Science & Engineering. Vol. vii. McGraw-Hill Professional. 2002. pp. 493–494. ISBN978-0-07-913665-7.
18. ^ ^{a b c} Considine, Glenn D., ed. (2005). Chemical Elements, in Van Nostrand's Encyclopedia of Chemical science. New York: Wiley-Interscience. p. 332. ISBN978-0-471-61525-five.
19. ^ National Nuclear Data Center (1990). "Tabular array of Isotopes disuse data". Brookhaven National Laboratory. Archived from the original on Oct 31, 2006. Retrieved April 4, 2007.
20. ^ National Nuclear Data Centre (2003). "Fr Isotopes". Brookhaven National Laboratory. Archived from the original on June thirty, 2007. Retrieved April iv, 2007.
21. ^ Winter, Marking. "Uses". Francium. The University of Sheffield. Retrieved March 25, 2007.
22. ^ ^{a b c d eastward} Emsley, John (2001). Nature'due south Building Blocks. Oxford: Oxford University Press. pp. 151–153. ISBN978-0-19-850341-five.
23. ^ Gagnon, Steve. "Francium". Jefferson Science Associates, LLC. Retrieved Apr i, 2007.
24. ^ Haverlock, T. J.; Mirzadeh, Due south.; Moyer, B. A. (2003). "Selectivity of calix[4]arene-bis(benzocrown-6) in the complexation and transport of francium ion". J Am Chem Soc. 125 (5): 1126–7. doi:10.1021/ja0255251. PMID 12553788.
25. ^ Gomez, Eastward.; Orozco, L A; Sprouse, G D (November 7, 2005). "Spectroscopy with trapped francium: advances and perspectives for weak interaction studies". Rep. Prog. Phys. 69 (1): 79–118. Bibcode:2006RPPh...69...79G. doi:10.1088/0034-4885/69/1/R02. S2CID 15917603.
26. ^ Peterson, I. (May 11, 1996). "Creating, cooling, trapping francium atoms" (PDF). Scientific discipline News. 149 (19): 294. doi:10.2307/3979560. JSTOR 3979560. Retrieved September xi, 2001.
27. ^ ^{a b c d e} Adloff, Jean-Pierre; Kaufman, George B. (September 25, 2005). Francium (Diminutive Number 87), the Last Discovered Natural Element Archived June iv, 2013, at the Wayback Machine . The Chemical Educator 10 (5). Retrieved on March 26, 2007.
28. ^ ^{a b c d eastward} Fontani, Marco (September 10, 2005). "The Twilight of the Naturally-Occurring Elements: Moldavium (Ml), Sequanium (Sq) and Dor (Do)". International Conference on the History of Chemical science. Lisbon. pp. 1–eight. Archived from the original on February 24, 2006. Retrieved Apr viii, 2007.
29. ^ ^{a b c d e} Van der Krogt, Peter (January 10, 2006). "Francium". Elementymology & Elements Multidict . Retrieved Apr 8, 2007.
30. ^ "Alabamine & Virginium". Time. February fifteen, 1932. Archived from the original on September 30, 2007. Retrieved April 1, 2007.
31. ^ MacPherson, H. G. (1934). "An Investigation of the Magneto-Optic Method of Chemical Analysis". Concrete Review. 47 (4): 310–315. Bibcode:1935PhRv...47..310M. doi:10.1103/PhysRev.47.310.
32. ^ Adloff, Jean-Pierre; Kauffman, George B. (2005). "Francium (Atomic Number 87), the Last Discovered Natural Element" (PDF). The Chemical Educator. 10 (5): 387–394. doi:x.1333/s00897050956a.
33. ^ Grant, Julius (1969). "Francium". Hackh's Chemical Dictionary. McGraw-Hill. pp. 279–280. ISBN978-0-07-024067-4.
34. ^ "History". Francium. State University of New York at Stony Brook. February twenty, 2007. Archived from the original on February iii, 1999. Retrieved March 26, 2007.
35. ^ Winter, Mark. "Geological information". Francium. The Academy of Sheffield. Retrieved March 26, 2007.
36. ^ Francium. Lenntech.
37. ^ ^{a b c} "Cooling and Trapping". Francium. State University of New York at Stony Brook. February twenty, 2007. Archived from the original on November 22, 2007. Retrieved May ane, 2007.
38. ^ "Production of Francium". Francium. State Academy of New York at Stony Brook. Feb xx, 2007. Archived from the original on Oct 12, 2007. Retrieved March 26, 2007.
39. ^ Orozco, Luis A. (September xxx, 2014). Project Closeout Study: Francium Trapping Facility at TRIUMF (Report). U.South. Department of Energy. doi:ten.2172/1214938.
40. ^ Tandecki, G; Zhang, J.; Collister, R.; Aubin, S.; Behr, J. A.; Gomez, E.; Gwinner, G.; Orozco, L. A.; Pearson, M. R. (2013). "Commissioning of the Francium Trapping Facility at TRIUMF". Journal of Instrumentation. 8 (12): P12006. arXiv:1312.3562. Bibcode:2013JInst...8P2006T. doi:10.1088/1748-0221/8/12/P12006. S2CID 15501597.
41. ^ Keller, Cornelius; Wolf, Walter; Shani, Jashovam. "Radionuclides, two. Radioactive Elements and Artificial Radionuclides". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:ten.1002/14356007.o22_o15.
42. ^ "Francium". Los Alamos National Laboratory. 2011. Retrieved Feb 19, 2012.

External links [edit]

• Francium at The Periodic Table of Videos (University of Nottingham)
• WebElements.com – Francium
• Stony Brook University Physics Dept.
• Scerri, Eric (2013). A Tale of Seven Elements, Oxford University Printing, Oxford, ISBN 9780195391312

What Group Is Francium In,

Source: https://en.wikipedia.org/wiki/Francium

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