Radon-195m

Properties and data of the isotope ^195mRn.

Contents

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

General data

Name of the isotope:Radon-195m; Rn-195mSymbol:^195mRn or 195m86RnMass number A:195 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:109Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.2674418604651 (= neutron-proton ratio)Neutron excess (N-Z):23Excitation energy:(59) keVIsotopic mass:195.00542(5) u (atomic weight of Radon-195m)Nuclide mass:194.9582478 u (calculated nuclear mass without electrons)Mass excess:5.0487 MeVMass defect:1.612008596 u (per nucleus)Nuclear binding energy:1501.57633512 MeV (per nucleus)
7.70039146 MeV (average binding energy per nucleon)Half-life:ca. 5 msDecay constant λ:138.62943611199 s^-1Specific activity α:4.281261495384 × 10⁺²³ Bq g^-1
11570977014553 Ci g^-1Spin and parity:
(nuclear angular momentum)13/2+

Radioactive Decay

Half-life T_½ = ca. 5 ms respectively 5 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹¹Po	~ 100 %

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
¹⁹⁵Rn		ca. 6 ms	3/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 109) and isobaric (same nucleon number A = 195) with Radon-195m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 109	Isobar A = 195
68	¹⁷⁷Er
69	¹⁷⁸Tm
70	¹⁷⁹Yb
71	¹⁸⁰Lu
72	¹⁸¹Hf
73	¹⁸²Ta
74	¹⁸³W	¹⁹⁵W
75	¹⁸⁴Re	¹⁹⁵Re
76	¹⁸⁵Os	¹⁹⁵Os
77	¹⁸⁶Ir	¹⁹⁵Ir
78	¹⁸⁷Pt	¹⁹⁵Pt
79	¹⁸⁸Au	¹⁹⁵Au
80	¹⁸⁹Hg	¹⁹⁵Hg
81	¹⁹⁰Tl	¹⁹⁵Tl
82	¹⁹¹Pb	¹⁹⁵Pb
83	¹⁹²Bi	¹⁹⁵Bi
84	¹⁹³Po	¹⁹⁵Po
85	¹⁹⁴At	¹⁹⁵At
86	¹⁹⁵Rn	¹⁹⁵Rn