Polonium-202

Properties and data of the isotope ²⁰²Po.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Polonium-202; Po-202Symbol:²⁰²Po or 20284PoMass number A:202 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:118Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.4047619047619 (= neutron-proton ratio)Neutron excess (N-Z):34Isotopic mass:201.980739(9) u (atomic weight of Polonium-202)Nuclide mass:201.9346637 u (calculated nuclear mass without electrons)Mass excess:-17.94151 MeVMass defect:1.699023776 u (per nucleus)Nuclear binding energy:1582.6304532 MeV (per nucleus)
7.83480422 MeV (average binding energy per nucleon)Separation energy:S_N = 9.492(10) MeV (first neutron)
S_P = 3.814(17) MeV (first proton)Half-life:44.6(4) minDecay constant λ:0.00025902361007472 s^-1Specific activity α:7.760580427459 × 10⁺¹⁷ Bq g^-1
20974541.695835 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.5281(177) femtometer fmYear of discovery:1951

Radioactive Decay

Half-life T_½ = 44.6(4) min (minutes) respectively 2.676 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹⁸Pb	1.92(7) %	5.7010(17) MeV
EC/β⁺	²⁰²Bi	98.08(7) %	2.800(18) MeV

Parent Nuclides

Direct parent isotopes are: ²⁰⁶Rn, ²⁰²At.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 118) and isobaric (same nucleon number A = 202) with Polonium-202. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 118	Isobar A = 202
72	¹⁹⁰Hf
73	¹⁹¹Ta
74	¹⁹²W
75	¹⁹³Re
76	¹⁹⁴Os	²⁰²Os
77	¹⁹⁵Ir	²⁰²Ir
78	¹⁹⁶Pt	²⁰²Pt
79	¹⁹⁷Au	²⁰²Au
80	¹⁹⁸Hg	²⁰²Hg
81	¹⁹⁹Tl	²⁰²Tl
82	²⁰⁰Pb	²⁰²Pb
83	²⁰¹Bi	²⁰²Bi
84	²⁰²Po	²⁰²Po
85	²⁰³At	²⁰²At
86	²⁰⁴Rn	²⁰²Rn
87	²⁰⁵Fr	²⁰²Fr
88	²⁰⁶Ra	²⁰²Ra
89	²⁰⁷Ac
90	²⁰⁸Th