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28 Si (the most abundant isotope, at 92.23%), 29 Si (4.67%), and 30 Si (3.1%) are stable. The longest-lived radioisotope is 32 Si, 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 32 P (which has a 14.27-day half ...
The only stable nuclides having an odd number of protons and an odd number of neutrons are hydrogen-2, lithium-6, boron-10, nitrogen-14 and (observationally) tantalum-180m. This is because the mass–energy of such atoms is usually higher than that of their neighbors on the same isobaric chain, so most of them are unstable to beta decay .
[13] 32 Si undergoes low-energy beta decay to 32 P and then stable 32 S. 31 Si may be produced by the neutron activation of natural silicon and is thus useful for quantitative analysis; it can be easily detected by its characteristic beta decay to stable 31 P, in which the emitted electron carries up to 1.48 MeV of energy. [34]
A barn (symbol: b) is a metric unit of area equal to 10 −28 m 2 (100 fm 2).This is equivalent to a square that is 10 −14 m (10 fm) each side, or a circle of diameter approximately 1.128 × 10 −14 m (11.28 fm).
Neutrons stabilize the nucleus, because they attract protons, which helps offset the electrical repulsion between protons. As a result, as the number of protons increases, an increasing ratio of neutrons to protons is needed to form a stable nucleus; if too many or too few neutrons are present with regard to the optimum ratio, the nucleus ...
In dimeric silicon dioxide there are two oxygen atoms bridging between the silicon atoms with an Si–O–Si angle of 94° and bond length of 164.6 pm and the terminal Si–O bond length is 150.2 pm. The Si–O bond length is 148.3 pm, which compares with the length of 161 pm in α-quartz. The bond energy is estimated at 621.7 kJ/mol. [21]
However, some even neutron numbers also have only one stable nuclide; these numbers are 0 (1 H), 2 (4 He), 4 (7 Li), 84 (142 Ce), 86 (146 Nd) and 126 (208 Pb), the case of 84 is special, since 142 Ce is theoretically unstable to double beta decay, and the nuclides with 84 neutrons which are theoretically stable to both beta decay and double ...
2 He 2+ On the other hand, carbon-14 decays by beta decay , whereby one neutron is transmuted into a proton with the emission of an electron and an antineutrino . Thus the atomic number increases by 1 ( Z : 6 → 7) and the mass number remains the same ( A = 14), while the number of neutrons decreases by 1 ( N : 8 → 7). [ 5 ]