Potassium-49

Properties and data of the isotope ⁴⁹K.

Contents

Potassium-49 is a radioisotope of the chemical element potassium, which has 30 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 49.

The discovery of the radioactive isotope was reported in 1972[1]; according to this report, potassium-49 was produced and identified as a fragmentation product during the irradiation of uranium templates with high-energy protons of an energy of 24 GeV.

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

General data

Name of the isotope:Potassium-49; K-49Symbol:⁴⁹K or 4919KMass number A:49 (= number of nucleons)Atomic number Z:19 (= number of protons)Neutrons N:30Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.5789473684211 (= neutron-proton ratio)Neutron excess (N-Z):11Isotopic mass:48.9682108(9) u (atomic weight of Potassium-49)Nuclide mass:48.957788 u (calculated nuclear mass without electrons)Mass excess:-29.61145 MeVMass defect:0.440412288 u (per nucleus)Nuclear binding energy:410.2414038 MeV (per nucleus)
8.37227355 MeV (average binding energy per nucleon)Separation energy:S_N = 5.3983(11) MeV (first neutron)
S_P = 14.546(17) MeV (first proton)Half-life:1.26(5) sDecay constant λ:0.55011680996821 s^-1Specific activity α:6.901835248015 × 10⁺²¹ Bq g^-1
186536087784.21 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2+)Magnetic dipole moment:μ(μ_N) = +1.3386(8)Nuclear g-factor:g_l = 0.8924Year of discovery:1972

Radioactive Decay

Half-life T_½ = 1.26(5) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁴⁹Ca	14 %	11.6885(8) MeV
β^-, n	⁴⁸Ca	86(9) %	6.5421(8) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 30) and isobaric (same nucleon number A = 49) with Potassium-49. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 30	Isobar A = 49
13	⁴³Al
14	⁴⁴Si
15	⁴⁵P
16	⁴⁶S	⁴⁹S
17	⁴⁷Cl	⁴⁹Cl
18	⁴⁸Ar	⁴⁹Ar
19	⁴⁹K	⁴⁹K
20	⁵⁰Ca	⁴⁹Ca
21	⁵¹Sc	⁴⁹Sc
22	⁵²Ti	⁴⁹Ti
23	⁵³V	⁴⁹V
24	⁵⁴Cr	⁴⁹Cr
25	⁵⁵Mn	⁴⁹Mn
26	⁵⁶Fe	⁴⁹Fe
27	⁵⁷Co	⁴⁹Co
28	⁵⁸Ni	⁴⁹Ni
29	⁵⁹Cu
30	⁶⁰Zn
31	⁶¹Ga
32	⁶²Ge
33	⁶³As
34	⁶⁴Se