High Quality Content by WIKIPEDIA articles! Moseley`s law is an empirical law concerning the characteristic x-rays that are emitted by atoms. The law was discovered and published by the English physicist Henry Moseley in 1913. It is historically important in quantitatively justifying the conception of the nuclear model of the atom, with all, or nearly all, positive charges of the atom located in the nucleus, and associated on an integer basis with atomic number. Until Moseley`s work, "atomic number" was merely an element`s place in the periodic table, and was not known to be associated with any measureable physical quantity. Moseley was able to show that the frequencies of certain characteristic X-rays emitted from chemical elements are proportional to the square of a number which was close to the element`s atomic number; a finding which supported van den Broek and Bohr`s model of the atom in which the atomic number is the same as the number of positive charges in the nucleus of the atom.