Final answer:
The periodic law states that when elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties. By studying the arrangement of elements in the periodic table, we can predict the physical and chemical properties of elements.
Step-by-step explanation:
The periodic law states that when elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties. This means that elements with similar properties are grouped together in the periodic table. By studying the arrangement of elements in the periodic table, we can predict the physical and chemical properties of elements.
For example, elements in the same group or column have similar electron configurations and therefore exhibit similar chemical behaviors. The alkali metals in Group 1, for instance, all have one valence electron and are highly reactive. Meanwhile, elements in the same period or row generally have the same number of electron shells and show similar trends in atomic radius and ionization energy.
Furthermore, the periodic table provides information about the periodic trends of elements. These include trends in atomic size, ionization energy, electronegativity, and metallic character. By understanding these trends, we can make predictions about how elements will react with other substances and how they will behave under different conditions.