According to the modern periodic law, the properties of elements are a periodic function of their: A. Atomic volume B. Atomic number C. Atomic weight D. Mass number
Option (b) is correct Mendeleev's periodic table was based on atomic mass. Though most of the elements could be arranged in the periodic table in the order of increasing atomic masses, there were some exceptions. For example, iodine (I) and tellurium (Te). In 1913, Moseley from his studies on X-rays found that the atomic number (i.e., proton number) is the fundamental property of an element and not its atomic mass. Thus, atomic number was adopted as the basis of the modern periodic table. The periodic law was then formulated as: The physical and chemical properties of elements are a periodic function of their atomic numbers.
