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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 ...
22 Si 9 12 Li 13 Be 14 B 15 C 16 N 17 O 18 F. 19 Ne ... There are no stable nuclides having an equal number of protons and neutrons in their nuclei with atomic number ...
Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive.
A nuclide is defined conventionally as an experimentally examined bound collection of protons and neutrons that either ... Many of these in ... 30 Si: 30: 14: 16: 8 ...
The neutron number (symbol N) is the number of neutrons in a nuclide. Atomic number (proton number) plus neutron number equals mass number: Z + N = A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N − Z = A − 2Z.
All atoms of a given element are not necessarily identical, however. The number of neutrons may vary to form different isotopes, and energy levels may differ, resulting in different nuclear isomers. For example, there are two stable isotopes of chlorine: 35 17 Cl with 35 − 17 = 18 neutrons and 37 17 Cl with 37 − 17 = 20 neutrons.
In many substances, thermal neutron reactions show a much larger effective cross-section than reactions involving faster neutrons, and thermal neutrons can therefore be absorbed more readily (i.e., with higher probability) by any atomic nuclei that they collide with, creating a heavier – and often unstable – isotope of the chemical element ...
The number of neutrons in a nucleus usually has very little effect on an element's chemical properties; except for hydrogen (for which the kinetic isotope effect is significant). Thus, all carbon isotopes have nearly identical chemical properties because they all have six electrons, even though they may have 6 to 8 neutrons.