C3-History of periodic table

C3-History of periodic table

1. Newlands 1864

   • Every 8th element had similar properties - Newlands' Octaves.
     • The pattern broke down on the 3rd row. He left no gaps for undiscovered elements.
       • Groups contained elements that didnt' have similar properties and he mixed up metals and non-metals

2. Dmitri Mendeleev-1869

   • Arranged elements in order of atomic mass like Newlands
     • Left gaps in order to keep elements with similar properties in same vertical columns
       • Newly discovered elements fit into his table perfectly.