Radon-203

Properties and data of the isotope ²⁰³Rn.

Content

General data

Name of the isotope:Radon-203; Rn-203Symbol:²⁰³Rn or 20386RnMass number A:203 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:117Isotopic mass:202.993394(2) u (atomic weight of Radon-203)Nuclide mass:202.9462218 u (calculated nuclear mass without electrons)Mass excess:-6.15345 MeVMass defect:1.693353924 u (per nucleus)Nuclear binding energy:1577.34902008 MeV (per nucleus)
7.77019222 MeV (average binding energy per nucleon)Half-life:44(2) sDecay constant λ:0.015753345012726 s^-1Specific activity α:4.696478350585 × 10⁺¹⁹ Bq g^-1
1269318473.1311 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2-)Year of discovery:1967

Radioactive Decay

Half-life T_½ = 44(2) s respectively 4.4 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹⁹Po	66(9) %	6.6299(21) MeV
EE/β⁺	²⁰³At	34(9) %	6.009(21) MeV

Parent Nuclides

Direct parent isotope is: ²⁰⁷Ra.

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
^203mRn	362(5) keV	26.9(5) s	(13/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 117) and isobaric (same nucleon number A = 203) with Radon-203. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 117	Isobar A = 203
71	¹⁸⁸Lu
72	¹⁸⁹Hf
73	¹⁹⁰Ta
74	¹⁹¹W
75	¹⁹²Re
76	¹⁹³Os	²⁰³Os
77	¹⁹⁴Ir	²⁰³Ir
78	¹⁹⁵Pt	²⁰³Pt
79	¹⁹⁶Au	²⁰³Au
80	¹⁹⁷Hg	²⁰³Hg
81	¹⁹⁸Tl	²⁰³Tl
82	¹⁹⁹Pb	²⁰³Pb
83	²⁰⁰Bi	²⁰³Bi
84	²⁰¹Po	²⁰³Po
85	²⁰²At	²⁰³At
86	²⁰³Rn	²⁰³Rn
87	²⁰⁴Fr	²⁰³Fr
88	²⁰⁵Ra	²⁰³Ra
89	²⁰⁶Ac
90	²⁰⁷Th