Polonium-210

Properties and data of the isotope ²¹⁰Po.

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-210; Po-210Other names:Radium FSymbol:²¹⁰Po or 21084PoMass number A:210 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:126Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.5 (= neutron-proton ratio)Neutron excess (N-Z):42Isotopic mass:209.9828736(12) u (atomic weight of Polonium-210)Nuclide mass:209.9367983 u (calculated nuclear mass without electrons)Mass excess:-15.95314 MeVMass defect:1.766208504 u (per nucleus)Nuclear binding energy:1645.21262422 MeV (per nucleus)
7.83434583 MeV (average binding energy per nucleon)Separation energy:S_N = 7.6584(14) MeV (first neutron)
S_P = 4.9834(8) MeV (first proton)Half-life:138.376(2) dDecay constant λ:5.797636014942 × 10^-8 s^-1Specific activity α:1.670534963474 × 10⁺¹⁴ Bq g^-1
4514.9593607427 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.5704(176) femtometer fmYear of discovery:1898

Radioactive Decay

Half-life T_½ = 138.376(2) d respectively 1.19556864 × 10⁷ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁰⁶Pb	100 %	5.40753(7) MeV

Parent Nuclides

Direct parent isotopes are: ²¹⁴Rn, ²¹⁰At, ²¹⁰Bi.

Occurrence

Comparison of the natural Polonium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Polonium Isotopic mixture	209.982872793 u	100 %
Isotope ²¹⁰Po	209.9828736(12) u	100 %	138.376(2) d	0+

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
^210mPo	5057.65(5) keV	263(5) ns	16+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 126) and isobaric (same nucleon number A = 210) with Polonium-210. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 126	Isobar A = 210
76	²⁰²Os
77	²⁰³Ir
78	²⁰⁴Pt
79	²⁰⁵Au	²¹⁰Au
80	²⁰⁶Hg	²¹⁰Hg
81	²⁰⁷Tl	²¹⁰Tl
82	²⁰⁸Pb	²¹⁰Pb
83	²⁰⁹Bi	²¹⁰Bi
84	²¹⁰Po	²¹⁰Po
85	²¹¹At	²¹⁰At
86	²¹²Rn	²¹⁰Rn
87	²¹³Fr	²¹⁰Fr
88	²¹⁴Ra	²¹⁰Ra
89	²¹⁵Ac	²¹⁰Ac
90	²¹⁶Th	²¹⁰Th
91	²¹⁷Pa	²¹⁰Pa
92	²¹⁸U
93	²¹⁹Np