Radon-205

Properties and data of the isotope ²⁰⁵Rn.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Radon-205; Rn-205Symbol:²⁰⁵Rn or 20586RnMass number A:205 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:119Isotopic mass:204.991723(5) u (atomic weight of Radon-205)Nuclide mass:204.9445508 u (calculated nuclear mass without electrons)Mass excess:-7.70998 MeVMass defect:1.712354756 u (per nucleus)Nuclear binding energy:1595.04818109 MeV (per nucleus)
7.78072283 MeV (average binding energy per nucleon)Separation energy:S_N = 7.811(9) MeV (first neutron)
S_P = 3.123(23) MeV (first proton)Half-life:170(4) sDecay constant λ:0.004077336356235 s^-1Specific activity α:1.203641856401 × 10⁺¹⁹ Bq g^-1
325308609.83822 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μ_N) = + 0.802(9)Quadrupole moment Q:0.062(6) barn (100 fm²)Nuclear g-factor:g_l = 0.3208Charge radius:5.5569(180) femtometer fmYear of discovery:1967

Radioactive Decay

Half-life T_½ = 170(4) s respectively 1.70 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁰¹Po	24.6(9) %	6.3865(18) MeV
EC/β⁺	²⁰⁵At	75.4(9) %	5.262(16) MeV

Parent Nuclides

Direct parent isotope is: ²⁰⁹Ra.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 119) and isobaric (same nucleon number A = 205) with Radon-205. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 119	Isobar A = 205
73	¹⁹²Ta
74	¹⁹³W
75	¹⁹⁴Re
76	¹⁹⁵Os
77	¹⁹⁶Ir	²⁰⁵Ir
78	¹⁹⁷Pt	²⁰⁵Pt
79	¹⁹⁸Au	²⁰⁵Au
80	¹⁹⁹Hg	²⁰⁵Hg
81	²⁰⁰Tl	²⁰⁵Tl
82	²⁰¹Pb	²⁰⁵Pb
83	²⁰²Bi	²⁰⁵Bi
84	²⁰³Po	²⁰⁵Po
85	²⁰⁴At	²⁰⁵At
86	²⁰⁵Rn	²⁰⁵Rn
87	²⁰⁶Fr	²⁰⁵Fr
88	²⁰⁷Ra	²⁰⁵Ra
89	²⁰⁸Ac	²⁰⁵Ac
90	²⁰⁹Th
91	²¹⁰Pa