"The elements which are the most widely diffused have small atomic weights"

This quote by Dmitri Mendeleev is referring to the table of elements of components, which he is credited with producing. He is suggesting that the components which are most extensively diffused, or spread out, have small atomic weights. This means that the elements which are most abundant in nature have reasonably low atomic weights. This is due to the fact that the lighter elements are more quickly spread out and can be discovered in more locations than the heavier components. This is because of the truth that lighter elements have less protons and neutrons in their nucleus, making them less dense and most likely to be discovered in different places. This is why the lighter components are more extensively diffused than the heavier elements. Mendeleev's quote is a testimony to his understanding of the periodic table and the elements that make it up.