Radon-217

Properties and data of the isotope ²¹⁷Rn.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Radon-217 is a radioisotope of the chemical element radon, which has 131 neutrons in its atomic nucleus in addition to the element-specific 86 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 217. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²¹⁷Rn is exclusively for academic purposes.

In 1949 a report appeared in which the short-lived isotope radon-217 was described for the first time. In the experiments presented there, a thorium-232 target was bombarded with 100–120 MeV α particles, so that via the decay chain starting from uranium-229 first thorium-225 and subsequently radium-221 were formed, from which the nuclide rn-217 finally arose. After chemical separation, the complete alpha-decay chains were analyzed, and one activity could be clearly assigned to the isotope radon-217 [1].

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

General data

Name of the isotope:Radon-217; Rn-217Symbol:²¹⁷Rn or 21786RnMass number A:217 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:131Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5232558139535 (= neutron-proton ratio)Neutron excess (N-Z):45Isotopic mass:217.003928(5) u (atomic weight of Radon-217)Nuclide mass:216.9567558 u (calculated nuclear mass without electrons)Mass excess:3.65891 MeVMass defect:1.804128748 u (per nucleus)Nuclear binding energy:1680.53510399 MeV (per nucleus)
7.7444014 MeV (average binding energy per nucleon)Separation energy:S_N = 4.666(7) MeV (first neutron)
S_P = 5.887(5) MeV (first proton)Half-life:0.54(5) msDecay constant λ:1283.6058899258 s^-1Specific activity α:3.56223754736 × 10⁺²⁴ Bq g^-1
96276690469270 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Year of discovery:1949

Radioactive Decay

Half-life T_½ = 0.54(5) ms respectively 5.4 × 10^-4 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹³Po	100 %	7.8872(29) MeV

Parent Nuclides

Direct parent isotopes are: ²²¹Ra, ²¹⁷At.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 131) and isobaric (same nucleon number A = 217) with Radon-217. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 131	Isobar A = 217
79	²¹⁰Au
80	²¹¹Hg
81	²¹²Tl	²¹⁷Tl
82	²¹³Pb	²¹⁷Pb
83	²¹⁴Bi	²¹⁷Bi
84	²¹⁵Po	²¹⁷Po
85	²¹⁶At	²¹⁷At
86	²¹⁷Rn	²¹⁷Rn
87	²¹⁸Fr	²¹⁷Fr
88	²¹⁹Ra	²¹⁷Ra
89	²²⁰Ac	²¹⁷Ac
90	²²¹Th	²¹⁷Th
91	²²²Pa	²¹⁷Pa
92	²²³U	²¹⁷U
93	²²⁴Np

External data and identifiers

Adopted Levels, Gammas:NuDat 217Rn

Literature and References

[1] - W. W. Meinke, A. Ghiorso, G. T. Seaborg:
Three Additional Collateral Alpha-Decay Chains.
In: Physical Review, 75, 314, (1949), DOI 10.1103/PhysRev.75.314.