Anand Classes explains the periodic table is not just a list of elements—it’s a powerful tool that reveals the underlying pattern in chemical behavior. This repeating pattern, known as periodicity, occurs because elements with similar valence shell electron configurations exhibit similar chemical and physical properties. As we move across periods or down groups, these patterns repeat at regular intervals due to the systematic arrangement of electrons, especially in the outermost shell. Understanding this cause of periodicity helps explain why elements in the same group behave alike in reactions and form similar compounds.