Americium-242m1

Properties and data of the isotope ²⁴²Am.

Content

General data

Name of the isotope:Americium-242m1; Am-242m1Symbol: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-242m1)
Excitation energy: 48.60(5) keVNuclide 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)Half-life:141(2) aDecay constant λ:1.558684912435 × 10^-10 s^-1Specific activity α:387876863592.69 Bq g^-1
10.483158475478 Ci g^-1Spin and parity:
(nuclear angular momentum)5-Magnetic dipole moment:μ(μ_N) = + 0.97(5)Quadrupole moment Q:6.5(2) barn (100 fm²)Nuclear g-factor:g_l = 0.194

Radioactive Decay

Half-life T_½ = 141(2) a respectively 4.447 × 10⁹ seconds s.

Decay mode	Daughter	Probability
Iso	²⁴²Am	99.55(2) %
α	²³⁸Np	0.45(2) %
SZ	^div	trace

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
²⁴²Am		16.02(2) h	1-
^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-242m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	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