Concept:The modern periodic table is organised by the fundamental property of the atom, not by chemical behaviour or weight.Explanation:Elements are placed in the table in order of increasing atomic number.Atomic number is the number of protons in the nucleus of an atom.This arrangement ensures that elements with similar electronic configurations fall in the same group.Oxidation number, mass number, and number of neutrons are not used as the primary basis for arranging the table.Answer:The periodic table is an arrangement of elements according to their Atomic number (Option B).