Potassium-51

Properties and data of the isotope ⁵¹K.

Contents

Potassium-51 is a radioisotope of the chemical element potassium, which has 32 neutrons in its atomic nucleus in addition to the element-specific 19 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 51.

The radioactive isotope was first mentioned in a report from 1983; according to this report, potassium-51 was observed and identified during the fragmentation of an iridium template with 10 GeV protons [1]. However, the actual discovery was not published until 1985 [2].

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

General data

Name of the isotope:Potassium-51; K-51Symbol:⁵¹K or 5119KMass number A:51 (= number of nucleons)Atomic number Z:19 (= number of protons)Neutrons N:32Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.6842105263158 (= neutron-proton ratio)Neutron excess (N-Z):13Isotopic mass:50.975829(14) u (atomic weight of Potassium-51)Nuclide mass:50.9654062 u (calculated nuclear mass without electrons)Mass excess:-22.51514 MeVMass defect:0.45012392 u (per nucleus)Nuclear binding energy:419.28773074 MeV (per nucleus)
8.22132805 MeV (average binding energy per nucleon)Separation energy:S_N = 4.859(15) MeV (first neutron)
S_P = 16.574(500) MeV (first proton)Half-life:365(5) msDecay constant λ:1.8990333713971 s^-1Specific activity α:2.287249292054 × 10⁺²² Bq g^-1
618175484339.14 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = +0.513(2)Nuclear g-factor:g_l = 0.342Year of discovery:1983

Radioactive Decay

Half-life T_½ = 365(5) ms respectively 3.65 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁵¹Ca	35 %	13.817(13) MeV
β^-, n	⁵⁰Ca	65(8) %	9.002(13) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 32) and isobaric (same nucleon number A = 51) with Potassium-51. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 32	Isobar A = 51
15	⁴⁷P
16	⁴⁸S
17	⁴⁹Cl	⁵¹Cl
18	⁵⁰Ar	⁵¹Ar
19	⁵¹K	⁵¹K
20	⁵²Ca	⁵¹Ca
21	⁵³Sc	⁵¹Sc
22	⁵⁴Ti	⁵¹Ti
23	⁵⁵V	⁵¹V
24	⁵⁶Cr	⁵¹Cr
25	⁵⁷Mn	⁵¹Mn
26	⁵⁸Fe	⁵¹Fe
27	⁵⁹Co	⁵¹Co
28	⁶⁰Ni	⁵¹Ni
29	⁶¹Cu
30	⁶²Zn
31	⁶³Ga
32	⁶⁴Ge
33	⁶⁵As
34	⁶⁶Se
35	⁶⁷Br
36	⁶⁸Kr

External data and identifiers

Adopted Levels, Gammas:NuDat 51K

Literature and References

[1] - M. Langevin, C. Détraz, D. Guillemaud-Mueller et al.:
⁵³K, ⁵⁴K and ⁵³Ca: Three new neutron rich isotopes.
In: Physics Letters B, 130, 5, (1983), DOI 10.1016/0370-2693(83)91135-8.

[2] - A. Huck, G. Klotz, A. Knipper et al.:
Beta decay of the new isotopes ⁵²K, ⁵²Ca, and ⁵²Sc; a test of the shell model far from stability.
In: Physical Review C, (1985), DOI 10.1103/PhysRevC.31.2226.