Americium-242
Properties and data of the isotope 242Am.
See also: list of Americium isotopes.
General data
Name of the isotope:Americium-242; Am-242Symbol:242Am or 24295AmMass number A:242 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:147Isotopic mass:242.0595474(12) u (atomic weight of Americium-242)Nuclide mass:242.0074395 u (calculated nuclear mass without electrons)Mass excess:55.46805 MeVMass defect:1.957573292 u (per nucleus)Nuclear binding energy:1823.46777606 MeV (per nucleus)
7.53499081 MeV (average binding energy per nucleon)Separation energy:SN = 5.53764(19) MeV (first neutron)
SP = 4.77607(19) MeV (first proton)Half-life:16.02(2) hDecay constant λ:1.201878174087 × 10-5 s-1Specific activity α:2.990859363983 × 10+16 Bq g-1
808340.36864424 Ci g-1Spin and parity:
(nuclear angular momentum)1-Magnetic dipole moment:μ(μN) = + 0.3879(15)Quadrupole moment Q:-2.40(70) barn (100 fm2)Nuclear g-factor:gl = 0.3879Year of discovery:1949
Radioactive Decay
Half-life T½ = 16.02(2) h (hours) respectively 5.7672 × 104 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
β- | 242Cm | 82.7(3) % | 0.663(4) MeV | |
EC | 242Pu | 17.3(3) % | 0.751(17) MeV | |
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 |
---|
242m1Am | 48.60(5) keV | 141(2) a | 5- |
242m2Am | 2200(80) keV | 14.0(10) ms | (2+,3-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 147) and isobaric (same nucleon number A = 242) with Americium-242. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
Z | Isotone N = 147 | Isobar A = 242 |
89 | 236Ac | |
90 | 237Th | |
91 | 238Pa | |
92 | 239U | 242U |
93 | 240Np | 242Np |
94 | 241Pu | 242Pu |
95 | 242Am | 242Am |
96 | 243Cm | 242Cm |
97 | 244Bk | 242Bk |
98 | 245Cf | 242Cf |
99 | 246Es | 242Es |
100 | 247Fm | 242Fm |
101 | 248Md | |
External data and identifiers
Last update: 2023-04-19
Perma link: https://www.chemlin.org/isotope/americium-242
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