Radon-228

Properties and data of the isotope ²²⁸Rn.

Content

General data

Name of the isotope:Radon-228; Rn-228Symbol:²²⁸Rn or 22886RnMass number A:228 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:142Isotopic mass:228.037835(19) u (atomic weight of Radon-228)Nuclide mass:227.9906628 u (calculated nuclear mass without electrons)Mass excess:35.24308 MeVMass defect:1.865535824 u (per nucleus)Nuclear binding energy:1737.73542684 MeV (per nucleus)
7.62164661 MeV (average binding energy per nucleon)Separation energy:S_N = 5.714(23) MeV (first neutron)
S_P = 9.53(30) MeV (first proton)Half-life:65(2) sDecay constant λ:0.010663802777845 s^-1Specific activity α:2.816619404858 × 10⁺¹⁹ Bq g^-1
761248487.79954 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1989

Radioactive Decay

Half-life T_½ = 65(2) s respectively 6.5 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²²⁸Fr	100 %	1.859(19) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 142) and isobaric (same nucleon number A = 228) with Radon-228. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 142	Isobar A = 228
84	²²⁶Po
85	²²⁷At	²²⁸At
86	²²⁸Rn	²²⁸Rn
87	²²⁹Fr	²²⁸Fr
88	²³⁰Ra	²²⁸Ra
89	²³¹Ac	²²⁸Ac
90	²³²Th	²²⁸Th
91	²³³Pa	²²⁸Pa
92	²³⁴U	²²⁸U
93	²³⁵Np	²²⁸Np
94	²³⁶Pu	²²⁸Pu
95	²³⁷Am
96	²³⁸Cm
97	²³⁹Bk
98	²⁴⁰Cf
99	²⁴¹Es
100	²⁴²Fm