Radon-229

Properties and data of the isotope ²²⁹Rn.

Contents

General Data

Radioactive Decay

Isotones und Isobares

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

General data

Name of the isotope:Radon-229; Rn-229Symbol:²²⁹Rn or 22986RnMass number A:229 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:143Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.6627906976744 (= neutron-proton ratio)Neutron excess (N-Z):57Isotopic mass:229.042257(14) u (atomic weight of Radon-229)Nuclide mass:228.9950848 u (calculated nuclear mass without electrons)Mass excess:39.36214 MeVMass defect:1.86977874 u (per nucleus)Nuclear binding energy:1741.68767764 MeV (per nucleus)
7.60562305 MeV (average binding energy per nucleon)Separation energy:S_N = 3.952(22) MeV (first neutron)
S_P = 9.61(40) MeV (first proton)Half-life:ca. 12 sDecay constant λ:0.057762265046662 s^-1Specific activity α:1.519006534934 × 10⁺²⁰ Bq g^-1
4105423067.3905 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:2009

Radioactive Decay

Half-life T_½ = ca. 12 s respectively 1.2 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²²⁹Fr	100 %	3.694(14) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 143) and isobaric (same nucleon number A = 229) with Radon-229. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 143	Isobar A = 229
84	²²⁷Po
85	²²⁸At	²²⁹At
86	²²⁹Rn	²²⁹Rn
87	²³⁰Fr	²²⁹Fr
88	²³¹Ra	²²⁹Ra
89	²³²Ac	²²⁹Ac
90	²³³Th	²²⁹Th
91	²³⁴Pa	²²⁹Pa
92	²³⁵U	²²⁹U
93	²³⁶Np	²²⁹Np
94	²³⁷Pu	²²⁹Pu
95	²³⁸Am	²²⁹Am
96	²³⁹Cm
97	²⁴⁰Bk
98	²⁴¹Cf
99	²⁴²Es
100	²⁴³Fm
101	²⁴⁴Md