Berkelium-249

Properties and data of the isotope ²⁴⁹Bk.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

See also: List of individual Berkelium isotopes (and general data sources).

General data

Name of the isotope:Berkelium-249; Bk-249Symbol:²⁴⁹Bk or 24997BkMass number A:249 (= number of nucleons)Atomic number Z:97 (= number of protons)Neutrons N:152Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.5670103092784 (= neutron-proton ratio)Neutron excess (N-Z):55Isotopic mass:249.0749832(13) u (atomic weight of Berkelium-249)Nuclide mass:249.0217785 u (calculated nuclear mass without electrons)Mass excess:69.8464 MeVMass defect:2.001112136 u (per nucleus)Nuclear binding energy:1864.02394801 MeV (per nucleus)
7.48603995 MeV (average binding energy per nucleon)Separation energy:S_N = 6.30(7) MeV (first neutron)
S_P = 4.8353(26) MeV (first proton)Half-life:330(4) dDecay constant λ:2.431242302911 × 10^-8 s^-1Specific activity α:58800335794247 Bq g^-1
1589.1982647094 Ci g^-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μ_N) = 2.0(4)Quadrupole moment Q:5.79 barn (100 fm²)Nuclear g-factor:g_l = 0.57142857142857Year of discovery:1954

Radioactive Decay

Half-life T_½ = 330(4) d respectively 2.851 × 10⁷ seconds s.

Decay mode	Daughter	Probability	Decay energy
β^-	²⁴⁹Cf	99.99855(8) %	0.1236(4) MeV
α	²⁴⁵Am	0.00145(8) %	5.5210(14) MeV
SZ	div	trace

Parent Nuclides

Direct parent isotopes are: ²⁵³Es, ²⁴⁹Cm.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^249mBk	8.777(14) keV	0.3 ms	3/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 152) and isobaric (same nucleon number A = 249) with Berkelium-249. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 152	Isobar A = 249
94	²⁴⁶Pu
95	²⁴⁷Am	²⁴⁹Am
96	²⁴⁸Cm	²⁴⁹Cm
97	²⁴⁹Bk	²⁴⁹Bk
98	²⁵⁰Cf	²⁴⁹Cf
99	²⁵¹Es	²⁴⁹Es
100	²⁵²Fm	²⁴⁹Fm
101	²⁵³Md	²⁴⁹Md
102	²⁵⁴No	²⁴⁹No
103	²⁵⁵Lr
104	²⁵⁶Rf
105	²⁵⁷Db
106	²⁵⁸Sg