Atomic mass molecular masses by comparing the vapor density of a collection of gases with molecules containing one or more of the chemical element in question. In the 20th century, until the 1960s chemists and physicists used two different atomic-mass scales. The chemists used a "atomic mass unit" (amu) scale such that the natural mixture of oxygen isotopes had an atomic mass 16, while the physicists assigned the same number 16 to only the atomic mass of the most common oxygen isotope (O, containing eight protons and eight neutrons). However, because oxygen-17 and oxygen-18 are also present in natural oxygen this led
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