Name of the isotope:Praseodymium-155; Pr-155Symbol:155Pr or 15559PrMass number A:155 (= number of nucleons)Atomic number Z:59 (= number of protons)Neutrons N:96Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.6271186440678 (= neutron-proton ratio)Neutron excess (N-Z):37Isotopic mass:154.940509(18) u (atomic weight of Praseodymium-155)Nuclide mass:154.9081452 u (calculated nuclear mass without electrons)Mass excess:-55.41551 MeVMass defect:1.352999824 u (per nucleus)Nuclear binding energy:1260.31121806 MeV (per nucleus) 8.13104012 MeV (average binding energy per nucleon)Separation energy:SN = 5.38(11) MeV (first neutron) SP = 10.48(20) MeV (first proton)Half-life:1.47(3) sDecay constant λ:0.44149501946493 s-1Specific activity α:1.715978067463 × 10+21 Bq g-1 46377785607.13 Ci g-1Spin and parity: (nuclear angular momentum)(3/2-)Year of discovery:1992
The following table shows the atomic nuclei that are isotonic (same neutron number N = 96) and isobaric (same nucleon number A = 155) with Praseodymium-155. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
