Development of the Periodic Table

Mendeleev’s Periodic Table

1. Proposed by Dmitri Mendeleev in 1869.
2. Based on the periodic recurrence of properties of elements when arranged in order of increasing atomic mass.
3. Contained 63 known elements at the time.
4. Mendeleev organized elements into rows and columns to form the periodic table.
5. He left gaps in the table for undiscovered elements and predicted their properties accurately, such as gallium (eka-aluminum) and g