Protactinium-218

Properties and data of the isotope ²¹⁸Pa.

Content

See also: list of Protactinium isotopes.

General data

Name of the isotope:Protactinium-218; Pa-218Symbol:²¹⁸Pa or 21891PaMass number A:218 (= number of nucleons)Atomic number Z:91 (= number of protons)Neutrons N:127Isotopic mass:218.020058(20) u (atomic weight of Protactinium-218)Nuclide mass:217.9701437 u (calculated nuclear mass without electrons)Mass excess:18.68391 MeVMass defect:1.792464244 u (per nucleus)Nuclear binding energy:1669.6696885 MeV (per nucleus)
7.65903527 MeV (average binding energy per nucleon)Separation energy:S_N = 6.456(24) MeV (first neutron)
S_P = 0.811(21) MeV (first proton)Half-life:113(10) μsDecay constant λ:6134.0458456632 s^-1Specific activity α:1.694499455224 × 10⁺²⁵ Bq g^-1
4.579728257363 × 10⁺¹⁴ Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:1979

Radioactive Decay

Half-life T_½ = 113(10) μs respectively 1.13 × 10^-4 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹⁴Ac	100 %	9.815(10) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 127) and isobaric (same nucleon number A = 218) with Protactinium-218. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 127	Isobar A = 218
76	²⁰³Os
77	²⁰⁴Ir
78	²⁰⁵Pt
79	²⁰⁶Au
80	²⁰⁷Hg
81	²⁰⁸Tl
82	²⁰⁹Pb	²¹⁸Pb
83	²¹⁰Bi	²¹⁸Bi
84	²¹¹Po	²¹⁸Po
85	²¹²At	²¹⁸At
86	²¹³Rn	²¹⁸Rn
87	²¹⁴Fr	²¹⁸Fr
88	²¹⁵Ra	²¹⁸Ra
89	²¹⁶Ac	²¹⁸Ac
90	²¹⁷Th	²¹⁸Th
91	²¹⁸Pa	²¹⁸Pa
92	²¹⁹U	²¹⁸U