The need for organizing the elements was recognized by many early chemists.
• Chemists used the properties of elements to sort them into groups.
• The periodic table we use today is based on the efforts of a Russian chemist, Dmitri Mendeleev and a German physicist, Lothar Mayer in 1869.
• Dmitri Mendeleev could not make a complete table, only had 63 elements leaving many spaces between elements for undiscovered ones.