What is the principle behind the construction of the long form of modern periodic table?
Atomic number
According to the modern periodic law, atomic number forms the basis of the construction of modern periodic table. Henry Moseley put forward the modern periodic law, which states that the properties of elements are the periodic functions of their atomic number i.e., if the elements are arranged in a tabular form in the increasing order of their atomic numbers then the properties of elements are repeated after definite regular intervals or periods.