Dobereiner's Triad

• Johannes Wolfgang Döbereiner,

  a German scientist who is known for his classification of elements

  which he called triads.
• (prefix tri- means “three”)
• Dobereiner's limitations

  
  

  only 5 Dobereiner's triads could be identified

  There also existed several elements at the time of Dobereiner’s triads formation that did

  not fit into Dobereiner’s triads.
• New elements could not be grouped in Dobereiner's triads
• These

  16 divisions resembled the atomic mass of oxygen, which,

  at that time, was the basis of the relative masses of

  elements.
• In every vertical strip, the elements with the same

  physical and chemical properties were grouped together.