Question

el silicio se encuentra en la naturaleza con tres isotopos que tienen las siguientes abundancias:
28 14 si(92,23%) 29 14 si(4,67%) 30 14 si(3,10%)
calcula la masa atómica (MA) promedio del silicio

Answer 1

Respuesta:Hola espro q esto te ayude lo hace todo mi hermana estudia quimica en la universidady esta practicando para un examen

Explicación:Silicon (14Si) has 23 known isotopes, with mass numbers ranging from 22 to 44. 28Si (the most abundant isotope, at 92.23%), 29Si (4.67%), and 30Si (3.1%) are stable. The longest-lived radioisotope is 32Si, which is produced by cosmic ray spallation of argon. Its half-life has been determined to be approximately 150 years (with decay energy 0.21 MeV), and it decays by beta emission to 32P (which has a 14.28-day half-life)[2] and then to 32S. After 32Si, 31Si has the second longest half-life at 157.3 minutes. All others have half-lives under 7 seconds.

A chart showing the relative abundances of the naturally occurring isotopes of silicon.

List of isotopes

Nuclide[3]

[n 1] Z N Isotopic mass (Da)[4]

[n 2][n 3] Half-life

[n 4] Decay

mode

[n 5] Daughter

isotope

[n 6] Spin and

parity

[n 7][n 4] Natural abundance (mole fraction)

Excitation energy Normal proportion Range of variation

22Si 14 8 22.03579(54)# 29(2) ms β+ (67.6%) 22Al 0+  

β+, p (32.4%) 21Mg

23Si 14 9 23.02544(54)# 42.3(4) ms β+ (12%) 23Al 3/2+#  

β+, p (88%) 21Mg

24Si 14 10 24.011535(21) 140(8) ms β+ (62.4%) 24Al 0+  

β+, p (37.6%) 23Mg

25Si 14 11 25.004109(11) 220(3) ms β+ (64.8%) 25Al 5/2+  

β+, p (35.2%) 24Mg

26Si 14 12 25.9923338(12) 2.2453(7) s β+ 26Al 0+  

27Si 14 13 26.98670469(12) 4.15(4) s β+ 27Al 5/2+  

28Si 14 14 27.9769265350(5) Stable 0+ 0.92223(19) 0.92205–0.92241

29Si 14 15 28.9764946653(6) Stable 1/2+ 0.04685(8) 0.04678–0.04692

30Si 14 16 29.973770137(23) Stable 0+ 0.03092(11) 0.03082–0.03102

31Si 14 17 30.97536319(5) 157.36(26) min β− 31P 3/2+  

32Si 14 18 31.9741515(3) 153(19) y β− 32P 0+ trace cosmogenic

33Si 14 19 32.9779770(8) 6.18(18) s β− 33P (3/2+)  

34Si 14 20 33.978575(15) 2.77(20) s β− 34P 0+  

34mSi 4256.1(4) keV <210 ns IT 34Si (3−)  

35Si 14 21 34.98455(4) 780(120) ms β− (94.74%) 35P 7/2−#  

36Si 14 22 35.98665(8) 450(60) ms β− (87.5%) 36P 0+  

β−, n (12.5%) 35P

37Si 14 23 36.99295(12) 90(60) ms β− (83%) 37P (7/2−)#  

β−, n (17%) 36P

38Si 14 24 37.99552(11) 90# ms [>1 μs] β−, n 37P 0+  

β− 38P

39Si 14 25 39.00249(15) 47.5(20) ms β− 39P 7/2−#  

40Si 14 26 40.00583(37) 33.0(10) ms β− 40P 0+  

41Si 14 27 41.01301(60) 20.0(25) ms β− 41P 7/2−#  

42Si 14 28 42.01768(54)# 12.5(35) ms β− 42P 0+  

43Si 14 29 43.02480(64)# 15# ms [>260 ns]   3/2−#  

44Si 14 30 44.03061(64)# 10# ms   0+  

mSi – Excited nuclear isomer.

( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

Modes of decay:

IT: Isomeric transition

n: Neutron emission

p: Proton emission

Bold symbol as daughter – Daughter product is stable.

( ) spin value – Indicates spin with weak assignment arguments.

References

Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.

Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:

Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.

Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references" (PDF). Chinese Physics C. 41 (3): 030003-1–030003-442. doi:10.1088/1674-1137/41/3/030003.

External links

Silicon isotopes data from The Berkeley Laboratory Isotopes Project's