1913年化学元素周期律进入了一个新的发展阶段,波尔(N.Bohr)提出了原子理论;索弟(F.Soddy)提出了位移规则和同位素概念;莫斯莱(H.Moseley)以X-射线谱为基础排列周期表中的元素,所以这一切都使周期律获得了新的理论基础,使周期律的含义得到了根本的修正。从此,核电荷(即原子序数)代替原子量作为元素分类的基础,使周期律中 In 1913, the periodic law of chemical elements entered a new stage of development. N. Bohr proposed the atomic theory; F. Soddy proposed the displacement rules and isotope concepts; and H. Moseley took X-ray spectra are based on the elements of the periodic table, so all of this gives new theoretical foundations for the periodic law, and the meaning of the periodic law has been fundamentally corrected. Since then, the nuclear charge (ie atomic number) has replaced the atomic weight as the basis for element classification, making the periodic law