Answer:
Order atomic arrangement
Explanation:
The periodic table is the arrangement of the atomic items in a systematic way. These elements are arranged are done from left to right and from top to the bottom. The sequence of the row is called periods and the number that is mentioned on the atomic elements shows the highest level of the energy level of those items. The elements that occupy the same column on the periodic table are called groups. Dmitri Mandleev was the father of periodic table