Calcium-40

Properties and data of the isotope ⁴⁰Ca.

Contents

General data

Name of the isotope:Calcium-40; Ca-40Symbol:⁴⁰Ca or 4020CaMass number A:40 (= number of nucleons)Atomic number Z:20 (= number of protons)Neutrons N:20Isotopic mass:39.9625909(2) u (atomic weight of Calcium-40)Nuclide mass:39.9516195 u (calculated nuclear mass without electrons)Mass excess:-34.84635 MeVMass defect:0.36720806 u (per nucleus)Nuclear binding energy:342.05210464 MeV (per nucleus)
8.55130262 MeV (average binding energy per nucleon)Separation energy:S_N = 15.6350(6) MeV (first neutron)
S_P = 8.32816(2) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:3.4776(19) femtometer fmYear of discovery:1922

Parent Nuclides

Direct parent isotopes are: ⁴⁰K, ⁴⁰Sc, ⁴¹Ti.

Occurrence

Comparison of the natural Calcium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	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 a	7/2-
Isotope ⁴²Ca	41.958618(1) u	0.647(23) %	stable	0+
Isotope ⁴³Ca	42.958766(2) u	0.135(10) %	stable	7/2-
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 a	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 20) and isobaric (same nucleon number A = 40) with Calcium-40. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 20	Isobar A = 40
8	²⁸O
9	²⁹F
10	³⁰Ne
11	³¹Na
12	³²Mg	⁴⁰Mg
13	³³Al	⁴⁰Al
14	³⁴Si	⁴⁰Si
15	³⁵P	⁴⁰P
16	³⁶S	⁴⁰S
17	³⁷Cl	⁴⁰Cl
18	³⁸Ar	⁴⁰Ar
19	³⁹K	⁴⁰K
20	⁴⁰Ca	⁴⁰Ca
21	⁴¹Sc	⁴⁰Sc
22	⁴²Ti	⁴⁰Ti
23	⁴³V	⁴⁰V
24	⁴⁴Cr
25	⁴⁵Mn
26	⁴⁶Fe
27	⁴⁷Co
28	⁴⁸Ni