{"id":241,"date":"2020-04-09T10:08:49","date_gmt":"2020-04-09T10:08:49","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=241"},"modified":"2023-08-15T14:34:08","modified_gmt":"2023-08-15T14:34:08","slug":"berkelium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/berkelium\/","title":{"rendered":"Berkelium (Bk)"},"content":{"rendered":"\n

Berkelium is a chemical element with the symbol Bk and the atomic number 97 in the periodic table of elements<\/a>. Since it\u2019s synthesized in a laboratory, berkelium is not found naturally in its elemental form in Earth\u2019s crust. Being a member of the actinide family of periodic table elements, this radioactive metal shares the physical and chemical properties with all the actinide elements of the group.<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Berkelium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>(Not provided)<\/td><\/tr>
Atomic number<\/td>97<\/td><\/tr>
Atomic weight (mass)<\/td>247.00 g.mol-1<\/td><\/tr>
Group (number)<\/td>3 (Actinides)<\/td><\/tr>
Period<\/td>7<\/td><\/tr>
Color<\/td>Silvery-white<\/td><\/tr>
Physical state<\/td>Solid (and relatively soft) metal at room temperature of 20\u00b0C<\/td><\/tr>
Half-life<\/td>4.5 hours<\/td><\/tr>
Electronegativity according to Pauling<\/td>1.3<\/td><\/tr>
Density<\/td>14.78 g.cm-3 at room temperature of 20\u00b0C<\/td><\/tr>
Melting point<\/td>986\u00b0C, 1807\u00b0F, 1259 K<\/td><\/tr>
Boiling point<\/td>2627 \u00b0C<\/td><\/tr>
Van der Waals radius<\/td>244 pm<\/td><\/tr>
Ionic radius<\/td>0.949\u00c5<\/td><\/tr>
Isotopes<\/td>14<\/td><\/tr>
Most characteristic isotope<\/td>247Bk, 249Bk<\/td><\/tr>
Electronic shell<\/td>[Rn] 5f9 7s2<\/td><\/tr>
The energy of the first ionization<\/td>(Not provided)<\/td><\/tr>
The energy of the second ionization<\/td>(Not provided)<\/td><\/tr>
Discovery date<\/td>In 1949 by Glenn. T. Seaborg, Albert Ghiorso, Stanley G. Thompson, and Kenneth Street, Jr.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Berkelium is a man-made radioactive metal that shares the chemical and physical properties with the neighbouring chemical elements californium (Cf)<\/a> and curium (Cm)<\/a>. With the periodic table symbol Bk, atomic number 97, atomic mass of 247.00 g.mol -1, and density of 14.78 g.cm-3 at 20\u00b0.C, berkelium is a relatively soft metal that can be diluted in aqueous inorganic acids. This reaction, in turn, releases gaseous hydrogen.  <\/span><\/p>\n\n\n\n

It has an electronegativity of 1.30 according to Pauling, and an electron configuration of Rn 5f9 7s2,<\/span> whereas the atomic radius according to van der Waals is 244 pm. This transuranic chemical element is reactive with other chemical elements, and mostly resembles the malleable and ductile rare earth element terbium <\/a>(Tb). <\/span><\/p>\n\n\n\n

The actinoide metals, such as curium, berkelium, and californium, share the same crystal structure with berkelium. Hence, this radioactive metal can occur as a double hexagonal, closest packed, and face centered cubic crystal.<\/span><\/p>\n\n\n\n

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How Was Berkelium Discovered?<\/span><\/h2>\n\n\n\n

This radioactive element was produced in 1949, at the University of California, Berkeley, California, USA. In an effort to better understand the chemical and physical properties of the transuranium elements, Glenn T. Seaborg, Albert Ghiorso, Stanley G. Thompson, and Kenneth Street, Jr. attempted to make a new chemical element by bombarding (i.e. induced radioactivity) the americium-241 isotope (produced in 1944) with alpha particles in an 60-inch cyclotron accelerator, triggering an ion exchange. The resulting electron-capture activity in this scientific trial was the production of isotope of the new element berkelium, the <\/span>243<\/span>Bk. <\/span><\/p>\n\n\n\n

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How Did Berkelium Get Its Name?<\/span><\/h2>\n\n\n\n

Berkelium (Bk) was named after the city of Berkeley, California, where the scientific experiment that produces the pure form of berkelium was first conducted. On the other hand, the University of Berkeley that housed the laboratories where this research in the realms of chemistry took place back in 1949, was named after the Anglo-Irish philosopher and scientist, Bishop George Berkeley. His greatest contribution to the world of science is his <\/span>Theory of idealism <\/span><\/i>that denies materialism and gives way to perception and thought. <\/span><\/p>\n\n\n\n

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Where Can You Find Berkelium?<\/span><\/h2>\n\n\n\n

SInce it cannot be found in Earth’s crust, microgram quantities of this powerful radioactive chemical substance are produced in nuclear reactors for scientific purposes.  <\/span><\/p>\n\n\n\n

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Berkelium in Everyday Life<\/span><\/h2>\n\n\n\n

Due to its rarity as a radioactive man-made chemical element, berkelium does not have any commercial use or practical applications in real life. This transuranium element is mainly used for scientific research, as a target for synthesizing of heavier chemical elements. <\/span><\/p>\n\n\n\n

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How Dangerous Is Berkelium?<\/span><\/h2>\n\n\n\n

Similar to the other chemical elements from the family of actinides in the periodic table, berkelium has a tendency to remain longest in the lungs and the bones upon accumulation. In comparison to the radioactive effects of the other actinides, berkelium is not so hazardous by itself due to its short half-life. However, after the expiration of its half-life, berkelium-249 decays into the more significantly radioactive californium-249 that imposes a much greater risk of radiation and toxicity. <\/span><\/p>\n\n\n\n

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Environmental Effects of Berkelium<\/span><\/h2>\n\n\n\n

The environmental effects of berkelium are rarely considered due to the fact that this is an element that does not occur in its elemental form in nature. On the other hand, the quantities of berkelium that are produced in chemical laboratories are extremely small. <\/span><\/p>\n\n\n\n

This fact shifts the focus to the environments where this actinide is produced, such as nuclear facilities, where the danger of exposure to berkelium\u2019s radioactivity is the biggest and imposes an extreme health hazard. The same holds true for the locations that have been affected by exposure to the radioactivity of other radioactive chemical elements. <\/span><\/p>\n\n\n\n

Namely, berkelium still ends up being one of the radioactive man-made metals in the periodic system of elements, making it a hazardous substance. Its radioactive properties can be recognized in locations where nuclear testings are conducted or a nuclear disaster has occured. <\/span><\/p>\n\n\n\n

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The Hydrogen Bomb of the U.S. Army <\/span><\/h3>\n\n\n\n

The Eniwetok Atoll in the Pacific is the location where the first nuclear weapon of the U.S. army was tested. The thermonuclear bomb, more familiar as the \u2018hydrogen bomb\u2019, held 1000 times more power than the atomic bomb. In 1952, it was dropped from the nowadays iconic American B52 jet bomber. After the nuclear testing, traces of berkelium were found in the locations where the effects of the hydrogen bomb were felt. <\/span><\/p>\n\n\n\n

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The Nuclear Accident in the Chernobyl Power Plant<\/span><\/h3>\n\n\n\n

In 1986, Ukraine became the location of the biggest nuclear accident in history. Upon an explosion of a nuclear reactor, there was widespread radiation triggered by the release of radioactive elements. Since radium, berkelium, plutonium, strontium<\/a>, and caesium <\/a>were used in the operation of this power plant, these radioactive elements saturated the air, covering enormous territories. <\/span><\/p>\n\n\n\n

The entire site was devastated by radiation, including the local wildlife and nature. Moreover, the hazardous effects of the radioactive components emitted after the explosion of the Chernobyl nuclear power plant affected not only the neighbouring countries of Ukraine, but also a large part of Europe. <\/span><\/p>\n\n\n\n

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What Is Radioactivity and What Are Its Health Hazards?<\/span><\/h3>\n\n\n\n

The radioactive atoms of a chemical element characterize an unstable nucleus. This instability occurs due to an imbalance between the number of neutrons and protons. When the scientists add protons or neutrons to a nucleus of an atom, they trigger its instability and the decay process of the element\u2019s isotope. At this point, the atom tries to release the unnecessary protons, neutrons, or positrons, via alpha, beta, or gamma decay mode.<\/span><\/p>\n\n\n\n

These radioactive modes of nucleus decay radiate ionizing radiation in the surrounding environment, which imposes an extreme health hazard. The exposure to radiation can lead to some severe and incurable diseases, as well as cancer on all tissues and organs of the body. <\/span><\/p>\n\n\n\n

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Isotopes of Berkelium<\/span><\/h2>\n\n\n\n

There are 18 unstable isotopes of berkelium with a mass number that ranges from <\/span>233<\/span>Bk to <\/span>253<\/span>Bk. All isotopes of this member of the actinide family of the periodic system are radioactive. <\/span>Having a half-life of 1,380 years, <\/span>247<\/span>Bk is the longest living and most stable isotope of berkelium. The berkelium-249 isotope decays into californium-249 and can be most easily reproduced.  <\/span><\/p>\n\n\n\n

The following is a tabular presentation of the berkelium isotopes, their decay mode, and half-life.<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n
Nuclide<\/b>\n

 <\/p>\n

[n 1]<\/span><\/p>\n<\/td>

Z<\/i><\/b><\/td>N<\/i><\/b><\/td>Isotopic mass <\/b>(Da)<\/span>\n

 <\/p>\n

[n 2][n 3]<\/span><\/p>\n<\/td>

Half-life<\/b><\/td>Decay<\/b>\n

 <\/p>\n

mode<\/b><\/p>\n

[n 4]<\/span><\/p>\n<\/td>

Daughter<\/b>\n

 <\/p>\n

isotope<\/b><\/p>\n<\/td>

Spin and<\/b>\n

 <\/p>\n

parity<\/b><\/p>\n

[n 5][n 6]<\/span><\/p>\n<\/td><\/tr>

Excitation energy<\/b>[n 6]<\/span><\/td><\/tr>
233<\/span>Bk<\/span>[2]<\/span><\/td>97<\/span><\/td>136<\/span><\/td> <\/td>21 s<\/span><\/td>\u03b1<\/span><\/td>229<\/span>Am<\/span><\/td> <\/td><\/tr>
234<\/span>Bk<\/span>[3]<\/span><\/td>97<\/span><\/td>137<\/span><\/td> <\/td>19(+6-4) s<\/span><\/td>\u03b1 (50%)<\/span><\/td>230<\/span>Am<\/span><\/td> <\/td><\/tr>
\u03b2<\/span>+<\/span> (50%)<\/span><\/td>234<\/span>Cm<\/span><\/td><\/tr>
236<\/span>Bk<\/span><\/td>97<\/span><\/td>139<\/span><\/td>236.05733(43)#<\/span><\/td>22(+13-6) s<\/span>[4]<\/span><\/td>\u03b1<\/span><\/td>232<\/span>Am<\/span><\/td> <\/td><\/tr>
\u03b2<\/span>+<\/span><\/td>236<\/span>Cm<\/span><\/td><\/tr>
238<\/span>Bk<\/span><\/td>97<\/span><\/td>141<\/span><\/td>238.05828(31)#<\/span><\/td>2.40(8) min<\/span><\/td>\u03b1<\/span><\/td>234<\/span>Am<\/span><\/td> <\/td><\/tr>
\u03b2<\/span>+<\/span>, <\/span>SF<\/span><\/a> (.048%)<\/span><\/td>(various)<\/span><\/td><\/tr>
\u03b2<\/span>+<\/span> (rare)<\/span><\/td>238<\/span>Cm<\/span><\/td><\/tr>
240<\/span>Bk<\/span><\/td>97<\/span><\/td>143<\/span><\/td>240.05976(16)#<\/span><\/td>4.8(8) min<\/span><\/td>\u03b2<\/span>+<\/span> (90%)<\/span><\/td>240<\/span>Cm<\/span><\/td> <\/td><\/tr>
\u03b1 (10%)<\/span><\/td>236<\/span>Am<\/span><\/td><\/tr>
\u03b2<\/span>+<\/span>, SF (.002%)<\/span><\/td>(various)<\/span><\/td><\/tr>
241<\/span>Bk<\/span><\/td>97<\/span><\/td>144<\/span><\/td>241.06023(22)#<\/span><\/td>4.6(4) min<\/span><\/td>\u03b1<\/span><\/td>237<\/span>Am<\/span><\/td>(7\/2+)<\/span><\/td><\/tr>
\u03b2<\/span>+<\/span> (rare)<\/span><\/td>241<\/span>Cm<\/span><\/td><\/tr>
242<\/span>Bk<\/span><\/td>97<\/span><\/td>145<\/span><\/td>242.06198(22)#<\/span><\/td>7.0(13) min<\/span><\/td>\u03b2<\/span>+<\/span> (99.99%)<\/span><\/td>242<\/span>Cm<\/span><\/td>2\u2212#<\/span><\/td><\/tr>
\u03b2<\/span>+<\/span>, SF (3\u00d710<\/span>\u22124<\/span>%)<\/span><\/td>(various)<\/span><\/td><\/tr>
242m<\/span>Bk<\/span><\/td>200(200)# keV<\/span><\/td>600(100) ns<\/span><\/td>SF<\/span><\/td>(various)<\/span><\/td> <\/td><\/tr>
243<\/span>Bk<\/span><\/td>97<\/span><\/td>146<\/span><\/td>243.063008(5)<\/span><\/td>4.5(2) h<\/span><\/td>\u03b2<\/span>+<\/span> (99.85%)<\/span><\/td>243<\/span>Cm<\/span><\/td>(3\/2\u2212)<\/span><\/td><\/tr>
\u03b1 (.15%)<\/span><\/td>239<\/span>Am<\/span><\/td><\/tr>
244<\/span>Bk<\/span><\/td>97<\/span><\/td>147<\/span><\/td>244.065181(16)<\/span><\/td>4.35(15) h<\/span><\/td>\u03b2<\/span>+<\/span> (99.99%)<\/span><\/td>244<\/span>Cm<\/span><\/td>(4\u2212)#<\/span><\/td><\/tr>
\u03b1 (.006%)<\/span><\/td>240<\/span>Am<\/span><\/td><\/tr>
245<\/span>Bk<\/span><\/td>97<\/span><\/td>148<\/span><\/td>245.0663616(25)<\/span><\/td>4.94(3) d<\/span><\/td>EC<\/span><\/a> (99.88%)<\/span><\/td>245<\/span>Cm<\/span><\/td>3\/2\u2212<\/span><\/td><\/tr>
\u03b1 (.12%)<\/span><\/td>241<\/span>Am<\/span><\/td><\/tr>
246<\/span>Bk<\/span><\/td>97<\/span><\/td>149<\/span><\/td>246.06867(6)<\/span><\/td>1.80(2) d<\/span><\/td>\u03b2<\/span>+<\/span> (99.8%)<\/span><\/td>246<\/span>Cm<\/span><\/td>2(\u2212)<\/span><\/td><\/tr>
\u03b1 (.2%)<\/span><\/td>242<\/span>Am<\/span><\/td><\/tr>
247<\/span>Bk<\/span><\/td>97<\/span><\/td>150<\/span><\/td>247.070307(6)<\/span><\/td>1.38(25)\u00d710<\/span>3<\/span> y<\/span><\/td>\u03b1<\/span><\/td>243<\/span>Am<\/span><\/td>(3\/2\u2212)<\/span><\/td><\/tr>
SF (rare)<\/span><\/td>(various)<\/span><\/td><\/tr>
248<\/span>Bk<\/span><\/td>97<\/span><\/td>151<\/span><\/td>248.07309(8)#<\/span><\/td>>300 y<\/span>[5]<\/span><\/a><\/td>\u03b1<\/span><\/td>244<\/span>Am<\/span><\/td>6+#<\/span><\/td><\/tr>
248m<\/span>Bk<\/span><\/td>30(70)# keV<\/span><\/td>23.7(2) h<\/span><\/td>\u03b2<\/span>\u2212<\/span><\/td>248<\/span>Cf<\/span><\/td>1(\u2212)<\/span><\/td><\/tr>
249<\/span>Bk<\/span>[n 7]<\/span><\/a><\/td>97<\/span><\/td>152<\/span><\/td>249.0749867(28)<\/span><\/td>330(4) d<\/span><\/td>\u03b2<\/span>\u2212<\/span><\/td>249<\/span>Cf<\/span><\/td>7\/2+<\/span><\/td><\/tr>
\u03b1 (.00145%)<\/span><\/td>245<\/span>Am<\/span><\/td><\/tr>
SF (4.7\u00d710<\/span>\u22128<\/span>%)<\/span><\/td>(various)<\/span><\/td><\/tr>
249m<\/span>Bk<\/span><\/td>8.80(10) keV<\/span><\/td>300 \u00b5s<\/span><\/td>IT<\/span><\/td>249<\/span>Bk<\/span><\/td>(3\/2\u2212)<\/span><\/td><\/tr>
250<\/span>Bk<\/span><\/td>97<\/span><\/td>153<\/span><\/td>250.078317(4)<\/span><\/td>3.212(5) h<\/span><\/td>\u03b2<\/span>\u2212<\/span><\/td>250<\/span>Cf<\/span><\/td>2\u2212<\/span><\/td><\/tr>
250m1<\/span>Bk<\/span><\/td>35.59(5) keV<\/span><\/td>29(1) \u00b5s<\/span><\/td>IT<\/span><\/td>250<\/span>Bk<\/span><\/td>(4+)<\/span><\/td><\/tr>
250m2<\/span>Bk<\/span><\/td>84.1(21) keV<\/span><\/td>213(8) \u00b5s<\/span><\/td> <\/td> <\/td>(7+)<\/span><\/td><\/tr>
251<\/span>Bk<\/span><\/td>97<\/span><\/td>154<\/span><\/td>251.080760(12)<\/span><\/td>55.6(11) min<\/span><\/td>\u03b2<\/span>\u2212<\/span><\/td>251<\/span>Cf<\/span><\/td>(3\/2\u2212)#<\/span><\/td><\/tr>
\u03b1 (10<\/span>\u22125<\/span>%)<\/span><\/td>247<\/span>Am<\/span><\/td><\/tr>
251m<\/span>Bk<\/span><\/td>35.5(13) keV<\/span><\/td>58(4) \u00b5s<\/span><\/td>IT<\/span><\/td>251<\/span>Bk<\/span><\/td>(7\/2+)#<\/span><\/td><\/tr>
252<\/span>Bk<\/span><\/td>97<\/span><\/td>155<\/span><\/td>252.08431(22)#<\/span><\/td>1.8(5) min<\/span><\/td>\u03b2<\/span>\u2212<\/span><\/td>252<\/span>Cf<\/span><\/td> <\/td><\/tr>
\u03b1<\/span><\/td>248<\/span>Am<\/span><\/td><\/tr>
253<\/span>Bk<\/span><\/td>97<\/span><\/td>156<\/span><\/td>253.08688(39)#<\/span><\/td>10# min<\/span><\/td>\u03b2<\/span>\u2212<\/span><\/td>253<\/span>Cf<\/span><\/td> <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Source: Wikipedia<\/span><\/p>\n\n\n\n

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List of Berkelium Compounds<\/span><\/h2>\n\n\n\n

The following is a list of some of the chemical compounds of berkelium:<\/span><\/p>\n\n\n\n