The elements in the periodic table are organised according to their electron configuration. The periodic table is arranged in order of increasing atomic number. The atomic number of an element corresponds to the number of positively charged protons in the nucleus of an atom of that element. The atomic number is also equivalent to the number of electrons in the first energy level.
Elements in each column have the same valence shell electron configurations, and the elements have some similar chemical properties. ... Similarity of valence shell electron configuration implies that we can determine the electron configuration of an atom solely by its position on the periodic table.