Silicon-31

Properties and data of the isotope ³¹Si.

Contents

General data

Name of the isotope:Silicon-31; Si-31Symbol:³¹Si or 3114SiMass number A:31 (= number of nucleons)Atomic number Z:14 (= number of protons)Neutrons N:17Isotopic mass:30.97536319(5) u (atomic weight of Silicon-31)Nuclide mass:30.9676832 u (calculated nuclear mass without electrons)Mass excess:-22.94904 MeVMass defect:0.28149083 u (per nucleus)Nuclear binding energy:262.2070192 MeV (per nucleus)
8.45829094 MeV (average binding energy per nucleon)Separation energy:S_N = 6.58739(4) MeV (first neutron)
S_P = 14.3732(29) MeV (first proton)Half-life:157.36(26) minDecay constant λ:7.346084833608 × 10^-5 s^-1Specific activity α:1.474638587901 × 10⁺¹⁸ Bq g^-1
39855096.9703 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Mirror nucleus:Chlorine-31Year of discovery:1934

Radioactive Decay

Half-life T_½ = 157.36(26) min respectively 9.4356 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	³¹P	100 %	1.49150(4) MeV	1266.2(14) keV 0.0554(7) %

Parent Nuclides

Direct parent isotope is: ³¹Al.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 17) and isobaric (same nucleon number A = 31) with Silicon-31. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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