Final answer:
The periodic law states that elements with similar properties occur in the same vertical column or group of the periodic table.
Step-by-step explanation:
The periodic law is a principle in chemistry that states that when elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties. In other words, elements with similar properties occur in the same vertical column or group of the periodic table. This arrangement allows scientists to easily predict the behavior of elements based on their position in the table.