Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are twenty known radioisotopes, from 233Bk and 233Bk to 253Bk (except 235Bk and 237Bk), and six nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.
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List of isotopes
Nuclide [n 1] | Z | N | Isotopic mass (Da)[3] [n 2][n 3] | Half-life[1] | Decay mode[1] [n 4] | Daughter isotope | Spin and parity[1] [n 5][n 6] | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy[n 6] | |||||||||||||||||||
233Bk | 97 | 136 | 233.05665(25)# | 40(30) s | α | 229Am | 3/2-# | ||||||||||||
β+? | 233Cm | ||||||||||||||||||
234Bk | 97 | 137 | 234.05732(16)# | 20(5) s | α (>80%) | 230Am | 3-# | ||||||||||||
β+ (<20%) | 234Cm | ||||||||||||||||||
β+, SF?[4] | (various) | ||||||||||||||||||
236Bk | 97 | 139 | 236.05748(39)# | 26(10) s | β+ (99.96%) | 236Cm | 4+# | ||||||||||||
β+, SF (0.04%) | (various) | ||||||||||||||||||
α? | 232Am | ||||||||||||||||||
238Bk | 97 | 141 | 238.05820(28)# | 2.40(8) min | β+ (99.95%) | 238Cm | 1# | ||||||||||||
β+, SF (0.048%) | (various) | ||||||||||||||||||
α? | 234Am | ||||||||||||||||||
239Bk | 97 | 142 | 239.05824(22)# | 100# s | β+ | 239Cm | (7/2+) | ||||||||||||
α? | 235Am | ||||||||||||||||||
SF? | (various) | ||||||||||||||||||
240Bk | 97 | 143 | 240.05976(16)# | 4.8(8) min | β+? | 240Cm | 7−# | ||||||||||||
β+, SF (0.0020%) | (various) | ||||||||||||||||||
α? | 236Am | ||||||||||||||||||
241Bk | 97 | 144 | 241.06010(18)# | 4.6(4) min | β+? | 241Cm | (7/2+) | ||||||||||||
α? | 237Am | ||||||||||||||||||
242Bk | 97 | 145 | 242.06198(22)# | 7.0(13) min | β+ | 242Cm | 3+# | ||||||||||||
β+, SF (<3×10−5%) | (various) | ||||||||||||||||||
α? | 238Am | ||||||||||||||||||
242mBk | 2000(200)# keV | 600(100) ns | SF | (various) | |||||||||||||||
IT? | 242Bk | ||||||||||||||||||
243Bk | 97 | 146 | 243.0630059(49) | 4.6(2) h | β+ (99.85%) | 243Cm | 3/2− | ||||||||||||
α (.15%) | 239Am | ||||||||||||||||||
244Bk | 97 | 147 | 244.065179(15) | 5.02(3) h | β+? | 244Cm | 4− | ||||||||||||
α (0.006%) | 240Am | ||||||||||||||||||
244mBk | 1500(500)# keV | 820(60) ns | SF | (various) | |||||||||||||||
IT? | 244Bk | ||||||||||||||||||
245Bk | 97 | 148 | 245.0663598(19) | 4.95(3) d | EC (99.88%) | 245Cm | 3/2− | ||||||||||||
α (.12%) | 241Am | ||||||||||||||||||
246Bk | 97 | 149 | 246.068671(64) | 1.80(2) d | β+ | 246Cm | 2(−) | ||||||||||||
α? | 242Am | ||||||||||||||||||
247Bk | 97 | 150 | 247.0703059(56) | 1.38(25)×103 y | α | 243Am | 3/2− | ||||||||||||
SF? | (various) | ||||||||||||||||||
248Bk | 97 | 151 | 248.073142(54) | >9 y | α? | 244Am | 6+# | ||||||||||||
EC? | 248Cm | ||||||||||||||||||
248mBk | −20(50) keV[n 7] | 23.7(2) h | β− (70%) | 248Cf | 1(−) | ||||||||||||||
EC (30%) | 248Cm | ||||||||||||||||||
α? | 244Am | ||||||||||||||||||
249Bk | 97 | 152 | 249.0749831(13) | 327.2(3) d | β− | 249Cf | 7/2+ | ||||||||||||
α (.00145%) | 245Am | ||||||||||||||||||
SF (4.7×10−8%) | (various) | ||||||||||||||||||
249mBk | 8.777(14) keV | 300 μs | IT | 249Bk | 3/2− | ||||||||||||||
250Bk | 97 | 153 | 250.0783172(31) | 3.212(5) h | β− | 250Cf | 2− | ||||||||||||
250m1Bk | 35.59(10) keV | 29(1) μs | IT | 250Bk | 4+ | ||||||||||||||
250m2Bk | 85.6(16) keV | 213(8) μs | IT | 250Bk | 7+ | ||||||||||||||
251Bk | 97 | 154 | 251.080761(12) | 55.6(11) min | β− | 251Cf | (3/2−) | ||||||||||||
251mBk | 35.5(13) keV | 58(4) μs | IT | 251Bk | (7/2+) | ||||||||||||||
252Bk | 97 | 155 | 252.08431(22)# | 1.8(5) min | β−? | 252Cf | |||||||||||||
α? | 248Am | ||||||||||||||||||
253Bk | 97 | 156 | 253.08688(39)# | 60# min | β−? | 253Cf | 3/2-# | ||||||||||||
This table header & footer: |
Actinides vs fission products
Actinides[5] by decay chain | Half-life range (a) | Fission products of 235U by yield[6] | ||||||
---|---|---|---|---|---|---|---|---|
4n | 4n + 1 | 4n + 2 | 4n + 3 | 4.5–7% | 0.04–1.25% | <0.001% | ||
228Ra№ | 4–6 a | 155Euþ | ||||||
244Cmƒ | 241Puƒ | 250Cf | 227Ac№ | 10–29 a | 90Sr | 85Kr | 113mCdþ | |
232Uƒ | 238Puƒ | 243Cmƒ | 29–97 a | 137Cs | 151Smþ | 121mSn | ||
248Bk[7] | 249Cfƒ | 242mAmƒ | 141–351 a | No fission products have a half-life | ||||
241Amƒ | 251Cfƒ[8] | 430–900 a | ||||||
226Ra№ | 247Bk | 1.3–1.6 ka | ||||||
240Pu | 229Th | 246Cmƒ | 243Amƒ | 4.7–7.4 ka | ||||
245Cmƒ | 250Cm | 8.3–8.5 ka | ||||||
239Puƒ | 24.1 ka | |||||||
230Th№ | 231Pa№ | 32–76 ka | ||||||
236Npƒ | 233Uƒ | 234U№ | 150–250 ka | 99Tc₡ | 126Sn | |||
248Cm | 242Pu | 327–375 ka | 79Se₡ | |||||
1.53 Ma | 93Zr | |||||||
237Npƒ | 2.1–6.5 Ma | 135Cs₡ | 107Pd | |||||
236U | 247Cmƒ | 15–24 Ma | 129I₡ | |||||
244Pu | 80 Ma | ... nor beyond 15.7 Ma[9] | ||||||
232Th№ | 238U№ | 235Uƒ№ | 0.7–14.1 Ga | |||||
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References
- Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.
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