Magic number (physics) from the work of Maria Mayer, the very strong evidence for the closed shells. It seemed a little like magic to him, and that is how the words 'Magic Numbers' were coined." Nuclei which have neutron number and proton (atomic) numbers each equal to one of the magic numbers are called "double magic", and are especially stable against decay. Examples of double magic isotopes include helium-4, oxygen-16, calcium-40, calcium-48, nickel-48, nickel-78, and lead-208. Double-magic effects may allow existence of stable isotopes which otherwise would not have been expected. An example is calcium-40, with 20 neutrons and 20 protons, which is
Atomic spacing frequency through the material, and using the laws of diffraction to determine its atomic spacing. Bond length can be determined between different elements in molecules by using the atomic radii of the atom. Carbon bonds with itself to form two covalent network solids. Diamond's C-C bond has a distance of 0.142 nm away from each carbon, while graphite's C-C bond has a distance of 0.341 nm away from each carbon. Although both bonds are between the same pair of elements they can still have different bond length. Atomic spacing Atomic spacing refers to the distance between the nuclei of atoms