Francium is the least electronegative of all the elements, therefore it should be the most chemically reactive alkali metal. This category only includes cookies that ensures basic functionalities and security features of the website. [30] They observed spectral lines which they presumed to be of eka-caesium. Discovered by. [29], In 1930, Fred Allison of the Alabama Polytechnic Institute claimed to have discovered element 87 (in addition to 85) when analyzing pollucite and lepidolite using his magneto-optical machine. As early as 1870, chemists thought that there should be an alkali metal beyond caesium, with an atomic number of 87. 2nd Francium metal. A. Francium (Fr) B. Potassium(K)) C. Magnesium (Mg) D. Nitrogen (N) I give you my guarantee the correct answer is: D. Nitrogen (N) Reason: As we go across a period from left to right atomic size decreases. air alkali metals cesium chemistry corrosion elements experiments explosion lithium metal potassium reaction rubidium science sodium water . Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Francium is the heaviest known member of the alkali metals series. [6] A heavy element with a single valence electron,[7] it has the highest equivalent weight of any element. It has a half-life of 22 minutes. (1). North America. With 87 protons the new element belonged in Group 1 of the periodic table, joining the other five alkali metals: lithium, sodium, potassium, rubidium and cesium. [28] Perey then suggested francium, after France. mass defect daughter half life nuclide. Free In-store Pickup. The Natural francium cannot be isolated in visible, weighable amounts, for only 24.5 grams (0.86 ounce) occur at any time in the entire crust of Adloff, Jean-Pierre; Kaufman, George B. [4] Francium has not been synthesized in amounts large enough to weigh. Prior to its discovery, it was referred to as eka-caesium. [1] The melting point is uncertain because of the element's extreme rarity and radioactivity; a different extrapolation based on Dmitri Mendeleev's method gave 20±1.5 °C (68±2.7 °F, 293±1.5 K). Were francium ever to be burned in air, the result is expected to be francium superoxide, FrO2. In 1925, he observed weak radioactivity in a sample of potassium, another alkali metal, and incorrectly concluded that eka-caesium was contaminating the sample (the radioactivity from the sample was from the naturally occurring potassium radioisotope, potassium-40). Energy of first ionisation. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. This bomb would use the violent reaction of francium,the most powerful alkali metal, with water. When element 87 in the periodic table (francium) does this, the extra proton means that it becomes element 88 (radium). [6] Its metastable isomer, francium-215m, is less stable still, with a half-life of only 3.5 ns. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). [30][31] In 1934, H.G. Earthquakes, whether natural or manmade , are capable of sending shockwaves deep through the earth. Francium, number 87, was the last of these elements to be discovered in nature. [23], Francium's ability to be synthesized, trapped, and cooled, along with its relatively simple atomic structure, has made it the subject of specialized spectroscopy experiments. Prior to its discovery, it was referred to as eka-caesium. Francium is the second rarest element in the Earth’s crust, next to astatine. Thus, helium is the smallest element, and francium is the largest. [20], Francium-221 has a half-life of 4.8 minutes. Francium is radioactive; less than 30g of it exists on Earth at any given time. [28] Further research into francium's structure was carried out by, among others, Sylvain Lieberman and his team at CERN in the 1970s and 1980s. Francium can be synthesized by 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 developed at the physics department of the State University of New York at Stony Brook in 1995. It is probably a very soft, easily cut, solid metal, perhaps even a liquid at room temperature. [13][14] Nearly all francium salts are water-soluble. So far as I know, nobody has ever assembled enough francium in one place to know for certain its appearance. [34] Francium was the last element discovered in nature, rather than synthesized, following hafnium and rhenium. The first effect was illumination of the water because of the underwater fireball. It can emit an alpha-particle to form astatine-208 or capture an orbital electron to form radon-212. Periodic Trends of Atomic Radius. It was assigned the symbol Fa, but this abbreviation was revised to the current Fr shortly thereafter. [29] They observed several weak emission lines, which they presumed to be those of element 87. This website uses cookies to improve your experience while you navigate through the website. Isotopes. These relativistic speeds lead to a significant contraction in the radius of all s orbitals as explained here. If you remember size of the atoms increases as you go down a column and it decreases as you go across the table. Francium and radium make up the s-block elements of the 7th period. [28] Research teams attempted to locate and isolate this missing element, and at least four false claims were made that the element had been found before an authentic discovery was made. [12], Francium coprecipitates with several caesium salts, such as caesium perchlorate, which results in small amounts of francium perchlorate. see all. Perey discovered that about 1% of actiniums radioactivity was caused by it emitting alpha particles, not beta particles. [4] Sensitive measurements of the light emitted and absorbed by the trapped atoms provided the first experimental results on various transitions between atomic energy levels in francium. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). Marguerite Perey in 1939. [30] In 1937, Hulubei's work was criticized by American physicist F. H. Hirsh Jr., who rejected Hulubei's research methods. Because of this, Jean Baptiste Perrin, Nobel Prize winner and Hulubei's mentor, endorsed moldavium as the true eka-caesium over Marguerite Perey's recently discovered francium. Alkali metals – properties and reactions. #Radius affected by the explosion. Various tests eliminated the possibility of the unknown element being thorium, radium, lead, bismuth, or thallium. Fr(s) + O2(g) → FrO2(s) International Union of Pure and Applied Chemistry, State University of New York at Stony Brook, "L'élément 87 : AcK, dérivé de l'actinium", "Creating, cooling, trapping francium atoms", Francium (Atomic Number 87), the Last Discovered Natural Element, "The Twilight of the Naturally-Occurring Elements: Moldavium (Ml), Sequanium (Sq) and Dor (Do)", "Francium (Atomic Number 87), the Last Discovered Natural Element", Project Closeout Report: Francium Trapping Facility at TRIUMF, Ullmann's Encyclopedia of Industrial Chemistry, https://en.wikipedia.org/w/index.php?title=Francium&oldid=998726143, Wikipedia indefinitely move-protected pages, Short description is different from Wikidata, Articles with Encyclopædia Britannica links, Creative Commons Attribution-ShareAlike License, This page was last edited on 6 January 2021, at 19:18. [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, but there are no experimental data to allow a refinement of the value for francium. In francium, the inner $\ce{s}$ electrons travel at roughly $\frac{[Z]}{[137]}$ or 64% the speed of light. It is the second-least electronegative element, following cesium. How can you tell which atom is larger? [29] He then published a thesis on his predictions of the properties of eka-caesium, in which he named the element russium after his home country. [5] Francium-223 also has a shorter half-life than the longest-lived isotope of each synthetic element up to and including element 105, dubnium. 375 kJ.mol-1. [32], In 1936, Romanian physicist Horia Hulubei and his French colleague Yvette Cauchois also analyzed pollucite, this time using their high-resolution X-ray apparatus. Scroll up a bit on this page to see it. The more the number of energy levels the bigger/larger the atomic /ionic radius. [note 1] Outside the laboratory, francium is extremely rare, with trace amounts found in uranium and thorium ores, where the isotope francium-223 continually forms and decays. Hi Michael, the quickest answer is that francium decays because it’s radioactive, which means its nucleus is unstable. It exists only in short-lived radioactive forms. This page was last updated: 10-Jan 06:20. [12] The CsFr molecule is predicted to have francium at the negative end of the dipole, unlike all known heterodiatomic alkali metal molecules. Francium-212 has a half-life of 19 minutes. [5][23][42], Image of light emitted by a sample of 200,000 francium atoms in a magneto-optical trap, Heat image of 300,000 francium atoms in a magneto-optical trap, ISOLDE Collaboration, J. Phys. [38] The original apparatus could trap up to a few thousand atoms, while a later improved design could trap over 300,000 at a time. Refined francium . Atomic radius and ionic radius depend on the number of energy levels occupied by electrons. Properties: The melting point of francium is 27 °C, its boiling point is 677 °C, and its valence is 1. The atomic radius of Francium is bigger/larger than that of sodium because Francium has … The largest amount produced in the laboratory was a cluster of more than 300,000 atoms. Refined Francium. Francium-221 has a half-life of 5 minutes. Electronic shell [ Rn ] 7s 1. There is no damage bonus when the target's signature radius is larger than the missile's explosion radius, however -- this is mostly a mechanism to make sure that the missiles used by large ships aren't too effective against small ships. From its position in the table, it was clear that element 87 would be a reactive alkali metal, the heaviest member of the family lithium, sodium, potassium, rubidium and caesium. [22][23][24][19] It has been used for research purposes in the fields of chemistry[25] 223 Francium has the longest half life at 21.8. It can emit an alpha-particle to form astatine-217 or a beta-particle to become radium-221. [38] Although the atoms only remain in the trap for about 30 seconds before escaping or undergoing nuclear decay, the process supplies a continual stream of fresh atoms. All elements discovered since then have been discovered when the element has been produced in the laboratory. Perey was curious about this finding, and already being an expert on actinium related work, she decided to carry out her own experiments on actinium. An atom gets larger as the number of electronic shells increase; therefore the radius of atoms increases as you go down a certain group in the periodic table of elements. These experiments have led to more specific information regarding energy levels and the coupling constants between subatomic particles. Francium is the heaviest known member of the alkali metals series. We also use third-party cookies that help us analyze and understand how you use this website. It was discovered in 1939 by Marguerite Perey. NUKEMAP is a mapping mash-up that calculates the effects of the detonation of a nuclear bomb. It is extremely reactive.Because of its high reactivity, it is a dangerous chemical. An atom is stable if the forces among the particles that make up the nucleus are balanced. Francium is a chemical element with the symbol Fr and atomic number 87. Hirsh was certain that eka-caesium would not be found in nature, and that Hulubei had instead observed mercury or bismuth X-ray lines. [21], Due to its instability and rarity, there are no commercial applications for francium. A. Francium (Fr) B. Potassium(K)) C. Magnesium (Mg) D. Nitrogen (N) I give you my guarantee the correct answer is: D. Nitrogen (N) Reason: As we go across a period from left to right atomic size decreases. A nuclear blast could kill or poison marine life, possibly disturbing the local ecosystem. Show only. An atom is unstable (radioactive) if these forces are unbalanced… An unstable nucleus will continually vibrate and contort and, sooner or later, attempt to reach stability by some combination of means: * converting one to the other with the ejection of a beta particle or positron. We know from witnesses and reporting that the Beirut explosion earlier this week caused massive damage within about a three-kilometre radius of the blast. It is the second-least electronegative element, following cesium. The isotopes of francium decay quickly into astatine, radium, and radon. (September 25, 2005). It’s January 11, 2015. Isotopes. However, it is used for research purposes to investigate atomic structure. 4. Ionic radius. This website uses cookies to improve your experience. The discovery began, in 1935, when Perey aged 26, read a research paper claiming that American scientists had discovered beta particles being emitted by actinium which had a higher amount of energy than normal. [5] All isotopes of francium decay into astatine, radium, or radon. In a 1-km (0.6-mile) radius, the peak pressure is four times that amount, and wind speeds can reach 756 km/h (470 mph). Bulk francium has never been viewed. It is used for research purposes only. Perey had discovered that actinium-227 could decay by emitting a helium nucleus (also called an alpha particle) from its own nucleus. If you would like to investigate this topic in a more advanced way, a good place to start is to search for information about the electric force between protons that tries to disintegrate the nucleus and the strong nuclear force that tries to hold the nucleus together. Community; Blocks, Tools, and Items; Refined Francium. Francium is a heavy, unstable, radioactive metal with a maximum half-life of only 22 minutes. [26] Studies on the light emitted by laser-trapped francium-210 ions have provided accurate data on transitions between atomic energy levels which are fairly similar to those predicted by quantum theory.[27]. Perey noticed decay particles with an energy level below 80 keV. Francium is element No. The bomb completely vaporized the island at ground zero. [3] It was the last element first discovered in nature, rather than by synthesis. It can emit an alpha-particle to form astatine-212 or a positron to form radon-216. unknown. As little as 20–30 g (one ounce) exists at any given time throughout the Earth's crust; the other isotopes (except for francium-221) are entirely synthetic. The discovery took place at the Curie Institute in Paris. [23] It is also calculated that there is a total mass of at most 30 g of francium in the Earth's crust at any given time.[36]. Francium is a chemical element with symbol Fr and atomic number 87. See each listing for international shipping options and costs. The element can be prepared by bombarding thorium with protons. The chemical element francium is classed as an alkali metal. [18], 223Fr can also be isolated from samples of its parent 227Ac, the francium being milked via elution with NH4Cl–CrO3 from an actinium-containing cation exchanger and purified by passing the solution through a silicon dioxide compound loaded with barium sulfate. Francium ceases to be francium and turns into astatine, radon or radium. 2nd Francium metal. Francium superoxide (FrO2) is expected to have a more covalent character than its lighter congeners; this is attributed to the 6p electrons in francium being more involved in the francium–oxygen bonding. [15], There are 34 known isotopes of francium ranging in atomic mass from 199 to 232. These cookies do not store any personal information. Blue-gray: Air blast (1.04-mile radius) — Air blasts are powerful enough to topple residential buildings. If the target's signature radius is smaller than the missile's explosion radius, there will be a penalty to the missile's damage. Only a … Minecraft default is 4.0 Radius: 4.0 #Should TNT break blocks DisableBreak: false #If enable blocks destroyed with the explosion will be restores RestoreBlocks: Enable: false #Minimum delay before blocks restore. Francium metal is produced by alpha decay in 227 Actinium 227. The discovery of francium completed humankind’s discoveries of naturally occurring elements. Hi RWhite84 and Amy. Commercially, there are no uses for francium, due to its rarity and instability. [16] Francium has seven metastable nuclear isomers. Discovered by. The fireball resulting from the detonation of the Tsar Bomba is estimated at 1.8 miles, with a thermal radiation radius … The francium atoms leave the gold target as ions, which are neutralized by collision with yttrium and then isolated in a magneto-optical trap (MOT) in a gaseous unconsolidated state. Francium was discovered by Marguerite Perey in 1939 when she was researching the radioactive decay of actinium-227. Soviet chemist D. K. Dobroserdov was the first scientist to claim to have found eka-caesium, or francium. Unfortunately this bomb will never be realized as francium is one of the most unstable elements with a half life of just minutes. [6] Liquid francium—if created—should have a surface tension of 0.05092 N/m at its melting point. This name was officially adopted by the International Union of Pure and Applied Chemistry (IUPAC) in 1949,[5] becoming the second element after gallium to be named after France. Ionic radius. It will additionally coprecipitate with many other caesium salts, including the iodate, the picrate, the tartrate (also rubidium tartrate), the chloroplatinate, and the silicotungstate. Chemistry Dictionary | Birth of the Elements | Tools | Periodic Table | Citing Chemicool | About | Privacy | Contact. Scientists there trapped up to ten thousand francium atoms at a time using laser beams in a magnetic field in order to measure their properties. Free Shipping. Free Returns. Allison requested that it be named virginium after his home state of Virginia, along with the symbols Vi and Vm. ... MARGUERY BLAST. Thanks for your question Nl. The radius of the hydrogen bomb depends upon its size and capacity. The new product exhibited chemical properties of an alkali metal (such as coprecipitating with caesium salts), which led Perey to believe that it was element 87, produced by the alpha decay of actinium-227. [6] It is the ninth product of the neptunium decay series as a daughter isotope of actinium-225. [37] Depending on the energy of the oxygen beam, the reaction can yield francium isotopes with masses of 209, 210, and 211. It may set itself on fire (ignite) in air. Radius of. 2nd Francium metal. The Baker nuclear test at Bikini Atoll in July 1946 was a shallow underwater explosion, part of Operation Crossroads.A 20 kiloton warhead was detonated in a lagoon which was approximately 200 ft (61 m) deep. But opting out of some of these cookies may affect your browsing experience. None are stable. That info is in the citation section. [29] All other previous purported discoveries of element 87 were ruled out due to francium's very limited half-life. The research project using this production method relocated to TRIUMF in 2012, where over 106 francium atoms have been held at a time, including large amounts of 209Fr in addition to 207Fr and 221Fr. It appears to be a laboratory cannon with a canister filled with Francium powders, the useless iron sights, and the electricity box. The Francium Launcher is a Special weapon introduced in the 15.3.0 update. Authorized Seller ... 9 results for francium. ), Abundance earth’s crust: ~ 0 parts per million, ~ 0 parts per million, Abundance solar system: ~ 0 parts per billion by weight, ~ 0 parts per billion by moles. Its use as a potential diagnostic aid for various cancers has also been explored,[5] but this application has been deemed impractical. [19] Francium-221 then decays into astatine-217 by alpha decay (6.457 MeV decay energy). Green: Radiation (0.74-mile radius) — Within at least 15 minutes of a blast, clouds of dust and sandlike radioactive particles — what's referred to as nuclear fallout — would reach the ground. The discovery took place at the Curie Institute in Paris. Marguerite Perey in 1939. A nucleus emits a beta-particle (an electron) and an antineutrino. Her first test put the alpha branching at 0.6%, a figure which she later revised to 1%. [10] 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. [17], Francium-223 is the most 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. Image Ref. An atom gets larger as the number of electronic shells increase; therefore the radius of atoms increases as you go down a certain group in the periodic table of elements. Unfortunately, it is not available in sufficient quantities to show it reacting with water – it is made in tiny quantities in particle accelerators. You don’t get hurt if you go near it, it has a larger explosion radius if it touches water, or a wet sponge, is obtained by cooking raw francium in a blast furnace, with lava, and only lava, as fuel. It is the second rarest natural element, following astatine. [18], Perey named the new isotope actinium-K (it is now referred to as francium-223)[28] and in 1946, she proposed the name catium (Cm) for her newly discovered element, as she believed it to be the most electropositive cation of the elements. Irène Joliot-Curie, one of Perey's supervisors, opposed the name due to its connotation of cat rather than cation; furthermore, the symbol coincided with that which had since been assigned to curium. (adsbygoogle = window.adsbygoogle || []).push({}); This uranium ore sample contains about 100 000 atoms of francium-223 (3.3 x 10 -20 g). These cookies will be stored in your browser only with your consent. [35], 223Fr is the result of the alpha decay of 227Ac and can be found in trace amounts in uranium minerals. Delivery Options. The element takes its name from the country of its discovery – France. Francium. The largest bomb as of August 2014, the 100 megaton Tsar Bomba, had a blast radius of 7.7 miles. Seaborg, Physical Review., 1950, 77, p765, Issue 6. Properties: The melting point of francium is 27 °C, its boiling point is 677 °C, and its valence is 1. Necessary cookies are absolutely essential for the website to function properly. The discovery began, in 1935, when Perey aged 26, read a research paper claiming that American scientists had discovered beta particles being emitted by actinium which had a higher a… It is mandatory to procure user consent prior to running these cookies on your website. [41], In 1996, the Stony Brook group trapped 3000 atoms in their MOT, which was enough for a video camera to capture the light given off by the atoms as they fluoresce. TKSST is an unprecedented collection of 4,500+ kid-friendly videos, curated for teachers and parents who want to share smarter, more meaningful media in the classroom and at home. An extremely small amount occurs naturally in uranium minerals, but it is so rare and radioactive that there has never been enough of it to actually see what would happen if a piece was dropped into water. Canada Only. Francium was discovered by Marguerite Perey in France (from which the element takes its name) in 1939. [28] Perey then attempted to determine the proportion of beta decay to alpha decay in actinium-227. It has a low melting point (27 oC, 81 oF) and, if enough of it could be accumulated, it would be liquid in a warm room. Francium was discovered by Marguerite Perey in 1939 when she was researching the radioactive decay of actinium-227. this may have been awnsered but why does francium decay? [6] In a given sample of uranium, there is estimated to be only one francium atom for every 1 × 1018 uranium atoms. Perey took pains to be accurate and detailed in her criticism of Hulubei's work, and finally she was credited as the sole discoverer of element 87. It is the second rarest natural element, following astatine. Less than thirty grams of francium exists on Earth at any given time. Francium-216 has a half-life of 0.7 microseconds. Francium (Fr), heaviest chemical element of Group 1 (Ia) in the periodic table, the alkali metal group. It was formerly known as eka-caesium and actinium K. It is one of the two least electronegative elements, the other being caesium.Francium is a highly radioactive metal that decays into astatine, radium, and radon.As an alkali metal, it has one valence electron. Unfortunately this bomb will never be realized as francium is one of the most unstable elements with a half life of just minutes. , 1 Comment, January 4, 2018 The optimal electron configuration of the 2P orbital contains 6 electrons, so since Fluorine is so close to ideal electron configuration, the electrons are held very tightly to the nucleus. Francium has been studied most recently at Stony Brook University, New York. Francium is a chemical element with the symbol Fr and atomic number 87. Nuclear blast could kill or poison marine life, possibly disturbing the local ecosystem francium, by adapting radiocaesium... Into astatine-217 by alpha decay ( 6.457 MeV decay energy ) into astatine-217 by alpha decay actinium-227! Discoveries of element 87 were ruled out due to its discovery – France are known, an! Prior to running these cookies on your website out of some of these on. ] a heavy element with the former being far more common then referred to by the provisional eka-caesium... Grams of francium is 27 °C, and its valence is 1 the more the number of bids and amounts. 46.4 °F, 281.0 K ) at Stony Brook University, New York a helium nucleus ) form! Polarizable than the Cs− ion this specific part of which I ’ ve quoted atoms. 3 ] it has the largest amount produced in the laboratory was a previously undiscovered element which she chose call... May have been awnsered but why does francium decay into astatine,,. Should be the most unstable elements with a maximum half-life of only 22.... Berkeley disproved the effectiveness of allison 's device and the electricity box measurements show very good agreement between values. Nucleus turns into a proton. ) the water because of this chemical... The only isotopes that occur in nature, with mass numbers 200 to 232, most commonly undergo alpha- beta-decay..., physical Review., 1950, 77, p765, Issue 6 the bigger/larger the /ionic. Island, the nucleus are balanced be francium superoxide, FrO2 of reaction with oxygen and moisture from the of! Any given time still, with a half life of just minutes the coupling constants subatomic. Elements of the most reactive element ] they observed spectral lines which they presumed to of! Option to opt-out of these cookies on your website referred to as eka-caesium been awnsered but why does francium?... ( also called an alpha particle ) from its own nucleus whose chemical properties mostly resemble of. A previously undiscovered element which she chose to call francium to honor her country! Fatalities within this radius prepared by bombarding thorium with protons is used for research purposes to investigate atomic.... Does francium decay which discusses this quantum theory ] 7s1, and is! Specific information regarding energy levels and the validity of his discovery user consent prior to running these may., Francium-221 has a nice summary part of which I ’ ve written a section francium... Caesium and the validity of his discovery each listing for international shipping options and costs purported of... Metal group Francium-221 then decays into astatine-217 by alpha decay in 227 actinium.... Was a previously undiscovered element which she later revised to 1 % alpha radioactive decay of actinium-227 the highest weight. Neutron converts to a significant contraction in the laboratory was a cluster of more than 300,000 atoms an! 227Ac and can be used to isolate francium, after France deep through the Earth astatine-217... Completely vaporized the island at ground zero ] francium has seven metastable isomers! Discovery – France unfortunately this bomb will never be realized as francium is the ninth product of the period... In trace amounts in uranium minerals francium explosion radius exists on Earth at any given time astatine... Stable if the forces among the particles that make up the nucleus are balanced,,... Astatine, radon or radium by synthesis form astatine-212 or a beta-particle to form radium-223 will stored... Use the violent reaction of francium, the most reactive metal a higher electron affinity caesium... Of more than 300,000 atoms by the provisional name eka-caesium the result is expected to be burned in,! By electrons than 30g of it exists on Earth at any one time commercial applications for,... Isotopes that occur in nature are either stable or unstable of actinium-227 than thirty grams of francium the... As francium is one of the unknown element being thorium, radium, and.. Website uses cookies to improve your experience while you navigate through the website and from... Its nucleus is unstable Ia ) in the periodic table, francium has the largest radius therefore should. The rapid production, and is the second-least electronegative element, following hafnium and rhenium decay... Means its nucleus is unstable the proportion of beta decay to alpha decay actinium-227!