Potassium-56

Properties and data of the isotope ⁵⁶K.

Contents

Potassium-56 is a radioisotope of the chemical element potassium, which has 37 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 56.

The discovery of the neutron-rich K nuclide was first reported in 2009; potassium-56, along with other isotopes, was produced and observed by irradiating a beryllium-9 template with germanium-76 ions (132 MeV/u) [1].

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

General data

Name of the isotope:Potassium-56; K-56Symbol:⁵⁶K or 5619KMass number A:56 (= number of nucleons)Atomic number Z:19 (= number of protons)Neutrons N:37Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.9473684210526 (= neutron-proton ratio)Neutron excess (N-Z):18Isotopic mass:56.008570(64) u (atomic weight of Potassium-56)Nuclide mass:55.9981472 u (calculated nuclear mass without electrons)Mass excess:7.9829 MeVMass defect:0.46070750000001 u (per nucleus)Nuclear binding energy:429.14627201 MeV (per nucleus)
7.66332629 MeV (average binding energy per nucleon)Separation energy:S_N = 0.562(781) MeV (first neutron)Half-life:> 620 nsDecay constant λ:1117979.3234838 s^-1Specific activity α:1.20225517223 × 10⁺²⁸ Bq g^-1
3.249338303337 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)(2-)Year of discovery:2009

Radioactive Decay

Half-life T_½ = > 620 ns respectively 6.2 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁵⁶Ca	100 %	21.49(65) MeV
β^-, xn ?

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 37) and isobaric (same nucleon number A = 56) with Potassium-56. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 37	Isobar A = 56
19	⁵⁶K	⁵⁶K
20	⁵⁷Ca	⁵⁶Ca
21	⁵⁸Sc	⁵⁶Sc
22	⁵⁹Ti	⁵⁶Ti
23	⁶⁰V	⁵⁶V
24	⁶¹Cr	⁵⁶Cr
25	⁶²Mn	⁵⁶Mn
26	⁶³Fe	⁵⁶Fe
27	⁶⁴Co	⁵⁶Co
28	⁶⁵Ni	⁵⁶Ni
29	⁶⁶Cu	⁵⁶Cu
30	⁶⁷Zn	⁵⁶Zn
31	⁶⁸Ga
32	⁶⁹Ge
33	⁷⁰As
34	⁷¹Se
35	⁷²Br
36	⁷³Kr
37	⁷⁴Rb
38	⁷⁵Sr
39	⁷⁶Y
40	⁷⁷Zr