Final answer:
The periodic table based solely on the atomic number of the elements is not as efficient as the modern periodic table because the modern version organizes elements based on electronic configurations and helps predict properties.
Step-by-step explanation:
The periodic table is based solely on the atomic number of the elements because it provides a more accurate way of organizing the elements and predicting their properties. The atomic number represents the number of protons in an atom's nucleus, which determines its chemical properties.
The modern periodic table is more efficient than the previous versions because it is organized in a way that reflects the electronic configurations of the elements. The elements are arranged in periods and groups, which helps to identify trends in properties and predict the behavior of new elements.
The biggest difference between the two is the organization and the ability to predict properties based on the modern periodic table's structure. It has proven to be more effective in understanding and exploring the behavior of elements.