Difference between modern and mendeleev's periodic table

mendeleev's periodic table is based on atomic mass modern periodic table is based on atomic number mendeleev's periodic table contains about 66 elements modern periodic table contains about 112 elements mendeleev's periodic table has gaps and under scope elements modern periodic table maintains uniformity in Mendeleev periodic table noble gases were not placed in modern periodic table gases in a separate group named as group 18 in mendeleev's periodic table transition elements included with other elements in modern periodic table transition elements placed in separate block

Mendeleev's was organized in atomic mass whereas the modern periodic table is organized by atomic number