The periodic table is one of the most important tools in science, or moreover, chemistry. In chemistry, scientists use the periodic table for almost every experiment they test and over the years, the periodic table has proven to be one of the best and most helpful discoveries in the field of science. Both the periodic table and the elements in the table have had a unique past and play a major role in the world …showed first 75 words of 800 total…

…showed last 75 words of 800 total…order by their increasing weight. He called the horizontal row periods and the vertical rows represented families of elements. However, he had to leave some gaps in his chart because he believed that some elements were not yet discovered and he later proved to be correct. Eventually the gaps in Mendeleev's charts were filled with real elements which were discovered over the years. Today, the periodic table has proven to be the cornerstone of chemistry.