Protactinium-238

Properties and data of the isotope ²³⁸Pa.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Protactinium-238; Pa-238Symbol:²³⁸Pa or 23891PaMass number A:238 (= number of nucleons)Atomic number Z:91 (= number of protons)Neutrons N:147Isotopic mass:238.054637(17) u (atomic weight of Protactinium-238)Nuclide mass:238.0047227 u (calculated nuclear mass without electrons)Mass excess:50.89404 MeVMass defect:1.931183564 u (per nucleus)Nuclear binding energy:1798.88590276 MeV (per nucleus)
7.55834413 MeV (average binding energy per nucleon)Separation energy:S_N = 4.705(21) MeV (first neutron)
S_P = 6.350(22) MeV (first proton)Half-life:2.28(10) minDecay constant λ:0.0050668653549704 s^-1Specific activity α:1.282074659074 × 10⁺¹⁹ Bq g^-1
346506664.61465 Ci g^-1Spin and parity:
(nuclear angular momentum)(3-)Year of discovery:1968

Radioactive Decay

Half-life T_½ = 2.28(10) min (minutes) respectively 1.368 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²³⁸U	100 %	3.586(16) MeV

Parent Nuclides

Direct parent isotope is: ²³⁸Th.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 147) and isobaric (same nucleon number A = 238) with Protactinium-238. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 147	Isobar A = 238
89	²³⁶Ac
90	²³⁷Th	²³⁸Th
91	²³⁸Pa	²³⁸Pa
92	²³⁹U	²³⁸U
93	²⁴⁰Np	²³⁸Np
94	²⁴¹Pu	²³⁸Pu
95	²⁴²Am	²³⁸Am
96	²⁴³Cm	²³⁸Cm
97	²⁴⁴Bk	²³⁸Bk
98	²⁴⁵Cf	²³⁸Cf
99	²⁴⁶Es
100	²⁴⁷Fm
101	²⁴⁸Md