Explain the classification of element by modern periodic table.

Modern periodic table is introduced by Henry Mosley in 1913. It is a modified version of Mendeleev’s Periodic Table. In this classification of elements, he arranged the elements in the increasing order of atomic number, based on the modern periodic law: The chemical and physical properties of the elements are periodic function of their atomic number.

Modern periodic table represents the electronic configuration of the elements. Elements are arranged in vertical columns called groups. and horizontal rows called periods. Elements under the same group have similar properties, whereas period represents the main energy level or shell. There are 7 periods and 18 groups in the new periodic table.

Based on the electronic configuration, the elements are divided into 4 blocks: s, p, d, and f block. The metals are arranged in the left hand side, and the non metals in the right hand side. There is a transition from metals to non-metals if one moves along a period.