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Beryllium ore with a US penny for scale Emerald is a naturally occurring compound of beryllium. The Sun has a concentration of 0.1 parts per billion (ppb) of beryllium. [28] Beryllium has a concentration of 2 to 6 parts per million (ppm) in the Earth's crust and is the 47th most abundant element. [29] [30] It is most concentrated in the soils ...
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 ...
Atomic number (Z): 4: Group: group 2 (alkaline earth metals) Period: period 2: Block s-block Electron configuration [] 2sElectrons per shell: 2, 2: Physical properties; Phase at STP: solid
Beryllium-8 is the only unstable nuclide with the same even number ≤ 20 of protons and neutrons. It is also one of the only two unstable nuclides (the other is helium-5) with mass number ≤ 143 which are stable to both beta decay and double beta decay.
Isotopes of lithium, beryllium, and boron are less strongly bound than helium, as shown by their increasing mass-to-mass number ratios. At carbon, the ratio of mass (in daltons) to mass number is defined as 1, and after carbon it becomes less than one until a minimum is reached at iron-56 (with only slightly higher values for iron-58 and nickel ...
Beryllium alloys are used for mechanical parts when stiffness, light weight, and dimensional stability are required over a wide temperature range. [69] [70] Beryllium-9 is used in small-scale neutron sources that use the reaction 9 Be + 4 He (α) → 12 C + 1 n, the reaction used by James Chadwick when he discovered the neutron.
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
For other isotopes, the isotopic mass is usually within 0.1 u of the mass number. For example, 35 Cl (17 protons and 18 neutrons) has a mass number of 35 and an isotopic mass of 34.96885. [7] The difference of the actual isotopic mass minus the mass number of an atom is known as the mass excess, [8] which for 35 Cl is –0.03115.