periodic law
Scientific term in chemistry: the principle that the properties of elements are periodic functions of their atomic numbers.
メンデレーエフは周期律を発見した。
Mendeleev discovered the periodic law.
周期律に基づいて元素が並べられている。
The elements are arranged based on the periodic law.
periodic table of the elements
Compound of 周期 (periodic cycle) and 律 (law, rule). A straightforward calque from Western scientific terminology.