Aluminium-28

Properties and data of the isotope ²⁸Al.

Content

General data

Name of the isotope:Aluminium-28; Al-28Symbol:²⁸Al or 2813AlMass number A:28 (= number of nucleons)Atomic number Z:13 (= number of protons)Neutrons N:15Isotopic mass:27.98191009(8) u (atomic weight of Aluminium-28)Nuclide mass:27.9747786 u (calculated nuclear mass without electrons)Mass excess:-16.85064 MeVMass defect:0.249789066 u (per nucleus)Nuclear binding energy:232.67701624 MeV (per nucleus)
8.30989344 MeV (average binding energy per nucleon)Separation energy:S_N = 7.72510(6) MeV (first neutron)
S_P = 9.55300(9) MeV (first proton)Half-life:2.245(2) minDecay constant λ:0.0051458588014844 s^-1Specific activity α:1.147743946217 × 10⁺²⁰ Bq g^-1
3102010665.4538 Ci g^-1Spin and parity:
(nuclear angular momentum)3+Magnetic dipole moment:μ(μ_N) = 3.241(5)Quadrupole moment Q:0.175(14) barn (100 fm²)Nuclear g-factor:g_l = 1.0803333333333Mirror nucleus:Phosphorus-28Year of discovery:1934

Radioactive Decay

Half-life T_½ = 2.245(2) min (minutes) respectively 1.347 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁸Si	100 %	4.64215(8) MeV

Parent Nuclides

Direct parent isotope is: ²⁸Mg.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 15) and isobaric (same nucleon number A = 28) with Aluminium-28. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 15	Isobar A = 28
5	²⁰B
6	²¹C
7	²²N
8	²³O	²⁸O
9	²⁴F	²⁸F
10	²⁵Ne	²⁸Ne
11	²⁶Na	²⁸Na
12	²⁷Mg	²⁸Mg
13	²⁸Al	²⁸Al
14	²⁹Si	²⁸Si
15	³⁰P	²⁸P
16	³¹S	²⁸S
17	³²Cl	²⁸Cl
18	³³Ar
19	³⁴K
20	³⁵Ca
21	³⁶Sc