Berkelium Berkelium is a transuranic radioactive chemical element with the symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence B ...

(₉₇Bk) is an

artificial element A synthetic element is one of 24 known chemical elements that do not occur naturally on Earth: they have been created by human manipulation of fundamental particles in a nuclear reactor, a particle accelerator, or the explosion of an atomic bomb ...

, and thus a

standard atomic weight The standard atomic weight of a chemical element (symbol ''A''r°(E) for element "E") is the weighted arithmetic mean of the relative isotopic masses of all isotopes of that element weighted by each isotope's abundance on Earth. For example, ...

cannot be given. Like all artificial elements, it has no

stable isotope The term stable isotope has a meaning similar to stable nuclide, but is preferably used when speaking of nuclides of a specific element. Hence, the plural form stable isotopes usually refers to isotopes of the same element. The relative abundanc ...

s. The first

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass num ...

to be synthesized was ²⁴³Bk in 1949. There are 19 known

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s, from ²³³Bk to ²⁵³Bk (with the exception of ²³⁵Bk and ²³⁷Bk), and 6

nuclear isomer A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ...

s. The longest-lived isotope is ²⁴⁷Bk with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ...

of 1,380 years.

List of isotopes

, - , ²³³Bk"Observation of new neutron-deficient isotopes with Z ≥ 92 in multinucleon transfer reactions" http://inspirehep.net/record/1383747/files/scoap3-fulltext.pdf , style="text-align:right" , 97 , style="text-align:right" , 136 , , 21 s , α , ²²⁹Am , , - , rowspan=2, ²³⁴Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 137 , rowspan=2, , rowspan=2, 19(+6−4) s , α (50%) , ²³⁰Am , rowspan=2, , - , β⁺ (50%) , ²³⁴Cm , - , rowspan=2, ²³⁶Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 139 , rowspan=2, 236.05733(43)# , rowspan=2, 22(+13−6) s , α , ²³²Am , rowspan=2, , - , β⁺ , ²³⁶Cm , - , rowspan=3, ²³⁸Bk , rowspan=3 style="text-align:right" , 97 , rowspan=3 style="text-align:right" , 141 , rowspan=3, 238.05828(31)# , rowspan=3, 2.40(8) min , α , ²³⁴Am , rowspan=3, , - , β⁺, SF (.048%) , (various) , - , β⁺ (rare) , ²³⁸Cm , - , rowspan=3, ²³⁹Bk , rowspan=3 style="text-align:right" , 97 , rowspan=3 style="text-align:right" , 142 , rowspan=3, 239.05828(25)# , rowspan=3, 100# s , β⁺ (>99%) , ²³⁹Cm , rowspan=3, (7/2+) , - , α (<1%) , ²³⁵Am , - , SF (<1%) , (various) , - , rowspan=3, ²⁴⁰Bk , rowspan=3 style="text-align:right" , 97 , rowspan=3 style="text-align:right" , 143 , rowspan=3, 240.05976(16)# , rowspan=3, 4.8(8) min , β⁺ (90%) , ²⁴⁰Cm , rowspan=3, , - , α (10%) , ²³⁶Am , - , β⁺, SF (.002%) , (various) , - , rowspan=2, ²⁴¹Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 144 , rowspan=2, 241.06023(22)# , rowspan=2, 4.6(4) min , α , ²³⁷Am , rowspan=2, (7/2+) , - , β⁺ (rare) , ²⁴¹Cm , - , rowspan=2, ²⁴²Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 145 , rowspan=2, 242.06198(22)# , rowspan=2, 7.0(13) min , β⁺ (99.99%) , ²⁴²Cm , rowspan=2, 2−# , - , β⁺, SF (3×10⁻⁴%) , (various) , - , style="text-indent:1em" , ^242mBk , colspan="3" style="text-indent:2em" , 200(200)# keV , 600(100) ns , SF , (various) , , - , rowspan=2, ²⁴³Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 146 , rowspan=2, 243.063008(5) , rowspan=2, 4.5(2) h , β⁺ (99.85%) , ²⁴³Cm , rowspan=2, (3/2−) , - , α (.15%) , ²³⁹Am , - , rowspan=2, ²⁴⁴Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 147 , rowspan=2, 244.065181(16) , rowspan=2, 4.35(15) h , β⁺ (99.99%) , ²⁴⁴Cm , rowspan=2, (4−)# , - , α (.006%) , ²⁴⁰Am , - , rowspan=2, ²⁴⁵Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 148 , rowspan=2, 245.0663616(25) , rowspan=2, 4.94(3) d , EC (99.88%) , ²⁴⁵Cm , rowspan=2, 3/2− , - , α (.12%) , ²⁴¹Am , - , rowspan=2, ²⁴⁶Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 149 , rowspan=2, 246.06867(6) , rowspan=2, 1.80(2) d , EC (99.8%) , ²⁴⁶Cm , rowspan=2, 2(−) , - , α (.2%) , ²⁴²Am , - , rowspan=2, ²⁴⁷Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 150 , rowspan=2, 247.070307(6) , rowspan=2, 1.38(25)×10³ y , α , ²⁴³Am , rowspan=2, (3/2−) , - , SF (rare) , (various) , - , ²⁴⁸Bk , style="text-align:right" , 97 , style="text-align:right" , 151 , 248.07309(8)# , >300 y , α , ²⁴⁴Am , 6+# , - , style="text-indent:1em" , ^248mBk , colspan="3" style="text-indent:2em" , 30(70)# keV , 23.7(2) h , β⁻ , ²⁴⁸Cf , 1(−) , - , rowspan=3, ²⁴⁹BkEasiest isotope to synthesize , rowspan=3 style="text-align:right" , 97 , rowspan=3 style="text-align:right" , 152 , rowspan=3, 249.0749867(28) , rowspan=3, 330(4) d , β⁻ , ²⁴⁹Cf , rowspan=3, 7/2+ , - , α (.00145%) , ²⁴⁵Am , - , SF (4.7×10⁻⁸%) , (various) , - , style="text-indent:1em" , ^249mBk , colspan="3" style="text-indent:2em" , 8.80(10) keV , 300 μs , IT , ²⁴⁹Bk , (3/2−) , - , ²⁵⁰Bk , style="text-align:right" , 97 , style="text-align:right" , 153 , 250.078317(4) , 3.212(5) h , β⁻ , ²⁵⁰Cf , 2− , - , style="text-indent:1em" , ^250m1Bk , colspan="3" style="text-indent:2em" , 35.59(5) keV , 29(1) μs , IT , ²⁵⁰Bk , (4+) , - , style="text-indent:1em" , ^250m2Bk , colspan="3" style="text-indent:2em" , 84.1(21) keV , 213(8) μs , , , (7+) , - , rowspan=2, ²⁵¹Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 154 , rowspan=2, 251.080760(12) , rowspan=2, 55.6(11) min , β⁻ , ²⁵¹Cf , rowspan=2, (3/2−)# , - , α (10⁻⁵%) , ²⁴⁷Am , - , style="text-indent:1em" , ^251mBk , colspan="3" style="text-indent:2em" , 35.5(13) keV , 58(4) μs , IT , ²⁵¹Bk , (7/2+)# , - , rowspan=2, ²⁵²Bk , rowspan=2 style="text-align:right" , 97 , rowspan=2 style="text-align:right" , 155 , rowspan=2, 252.08431(22)# , rowspan=2, 1.8(5) min , β⁻ , ²⁵²Cf , rowspan=2, , - , α , ²⁴⁸Am , - , ²⁵³Bk , style="text-align:right" , 97 , style="text-align:right" , 156 , 253.08688(39)# , 10# min , β⁻ , ²⁵³Cf ,

Actinides vs fission products

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Berkelium

List of isotopes

Actinides vs fission products

See also

References