See also: List of individual Calcium isotopes (and general data sources).
General data
Name of the isotope:Calcium-42; Ca-42Symbol:42Ca or 4220CaMass number A:42 (= number of nucleons)Atomic number Z:20 (= number of protons)Neutrons N:22Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.1 (= neutron-proton ratio)Neutron excess (N-Z):2Isotopic mass:41.958618(1) u (atomic weight of Calcium-42)Nuclide mass:41.9476466 u (calculated nuclear mass without electrons)Mass excess:-38.54708 MeVMass defect:0.388510792 u (per nucleus)Nuclear binding energy:361.89547168 MeV (per nucleus) 8.61655885 MeV (average binding energy per nucleon)Separation energy:SN = 11.48067(6) MeV (first neutron) SP = 10.27667(15) MeV (first proton)Half-life:stableSpin and parity: (nuclear angular momentum)0+Charge radius:3.5081(21) femtometer fmMirror nucleus:Titanium-42Year of discovery:1934
Comparison of the natural Calcium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
Atomic Mass ma
Quantity
Half-life
Spin
Calcium Isotopic mixture
40.078 u
100 %
Isotope 40Ca
39.9625909(2) u
96.941(156) %
stable
0+
Isotope 41Ca
40.96227792(15) u
[trace]
9.94(15) × 104 years
7/2-
Isotope 42Ca
41.958618(1) u
0.647(23) %
stable
0+
Isotope 44Ca
43.955482(2) u
2.086(110) %
stable
0+
Isotope 46Ca
45.95369(2) u
0.004(3) %
stable
0+
Isotope 48Ca
47.952522654(19) u
0.187(21) %
5.3 × 1019 years
0+
Isotope 43Ca
42.95876638(24) u
0.135(10) %
stable
7/2-
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 22) and isobaric (same nucleon number A = 42) with Calcium-42. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
