unit 3

THE EARLY PERIODIC TABLE

• First suggestions from John Daltion, arranged elements in order of mass.
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• John newlands built on Daltons ideas with law of ocatves - every eighth element seemed similar.
• John had many mistakes- he assumed every elemnt had been found (even though new ones kept turning up)
• Filled in all the gaps regardless of the fact some elements werent similar at all.
• Even put 2 elements in the same place - other sceintists dfidnt accept this

•  In 1869 Mendleev left gaps and arranged elements in order of mass.
• Other scienttists did almost the exact same - reliable.