Silicon-24

Properties and data of the isotope ²⁴Si.

Contents

Silicon-24 is a radioisotope of the chemical element silicon, which has 10 neutrons in its atomic nucleus in addition to the element-specific 14 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 24. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²⁴Si is exclusively for academic purposes.

The discovery of the proton-rich isotope was reported in 1979 [1]: According to this report, silicon-24 was produced by irradiating a magnesium-24 containing template with helium-3 nuclei at an energy of 70 MeV according to the nuclear reaction:

²⁴Mg(³He,3n)²⁴Si.

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

General data

Name of the isotope:Silicon-24; Si-24Symbol:²⁴Si or 2414SiMass number A:24 (= number of nucleons)Atomic number Z:14 (= number of protons)Neutrons N:10Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):0.71428571428571 (= neutron-proton ratio)Neutron excess (N-Z):-4Isotopic mass:24.011535(21) u (atomic weight of Silicon-24)Nuclide mass:24.003855 u (calculated nuclear mass without electrons)Mass excess:10.74478 MeVMass defect:0.184664608 u (per nucleus)Nuclear binding energy:172.01397436 MeV (per nucleus)
7.16724893 MeV (average binding energy per nucleon)Separation energy:S_N = 21.276(501) MeV (first neutron)
S_P = 3.292(19) MeV (first proton)Half-life:141.4(15) msDecay constant λ:4.9020309799147 s^-1Specific activity α:1.230030044200 × 10⁺²³ Bq g^-1
3324405524867 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Mirror nucleus:Neon-24Year of discovery:1979

Radioactive Decay

Half-life T_½ = 141.4(15) ms respectively 1.414 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	²⁴Al	67.6 %	10.794(19) MeV
β⁺, p	²³Mg	32.4(13) %	8.939 MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 10) and isobaric (same nucleon number A = 24) with Silicon-24. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 10	Isobar A = 24
3	¹³Li
4	¹⁴Be
5	¹⁵B
6	¹⁶C
7	¹⁷N	²⁴N
8	¹⁸O	²⁴O
9	¹⁹F	²⁴F
10	²⁰Ne	²⁴Ne
11	²¹Na	²⁴Na
12	²²Mg	²⁴Mg
13	²³Al	²⁴Al
14	²⁴Si	²⁴Si
15	²⁵P	²⁴P
16	²⁶S