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Thus, for high-energy neutrons, beryllium is a neutron multiplier, releasing more neutrons than it absorbs. This nuclear reaction is: [16] 9 4 Be + n → 2 4 2 He + 2 n. Neutrons are liberated when beryllium nuclei are struck by energetic alpha particles [15] producing the nuclear reaction 9 4 Be + 4 2 He → 12 6 C + n. where 4 2 He is an ...
Beryllium is unique as being the only monoisotopic element with both an even number of protons and an odd number of neutrons. There are 25 other monoisotopic elements but all have odd atomic numbers, and even numbers of neutrons. Of the 10 radioisotopes of beryllium, the most stable are 10 Be with a half-life of 1.387(12) million years [nb 1 ...
No odd-neutron-number isotope is the most naturally abundant isotope in its element, except for beryllium-9 (which is the only stable beryllium isotope), nitrogen-14, and platinum-195. No stable nuclides have a neutron number of 19, 21, 35, 39, 45, 61, 89, 115, 123, or ≥ 127.
Beryllium (Be) is the chemical element with atomic number 4, occurring in the form of 9 Be. At standard temperature and pressure, beryllium is a strong, steel-grey, light-weight, brittle, bivalent alkaline earth metal, with a density of 1.85 g⋅cm −3. [12] It also has one of the highest melting points of all the light metals.
Since a nucleus with an odd number of protons is relatively less stable, odd-numbered elements tend to have fewer stable isotopes. Of the 26 "monoisotopic" elements that have only a single stable isotope, all but one have an odd atomic number—the single exception being beryllium. In addition, no odd-numbered element has more than two stable ...
The single monoisotopic exception to the odd Z rule is beryllium; its single stable, primordial isotope, beryllium-9, has 4 protons and 5 neutrons. This element is prevented from having a stable isotope with equal numbers of neutrons and protons ( beryllium-8 , with 4 of each) by its instability toward alpha decay , which is favored due to the ...
Some isotopes undergo spontaneous fission (SF) with emission of neutrons.The most common spontaneous fission source is the isotope californium-252. 252 Cf and all other SF neutron sources are made by irradiating uranium or a transuranic element in a nuclear reactor, where neutrons are absorbed in the starting material and its subsequent reaction products, transmuting the starting material into ...
Two examples of isotopes that emit neutrons are beryllium-13 (decaying to beryllium-12 with a mean life 2.7 × 10 −21 s) and helium-5 (helium-4, 7 × 10 −22 s). [1] In tables of nuclear decay modes, neutron emission is commonly denoted by the abbreviation n.