Question
Thu May 29, 2008 By: Ravi Teja Devarakonda

Why was Mandaleev's periodic table discarded?

Expert Reply
Tue June 17, 2008
  1. Anamolous position of Hydrogen(It behaves both as metals-non-metals)
  2. They were arranged in position of increasing atomic masses .But there were some anamolies.Like argon was placed before potassium based on properties.
  3. As Mass was chosen as the basis positioning of isotopes was anamolous.
  4. Some elements with similar properties were grouped apart and some having dissimilar properties were grouped together.For eg. copper and mercury have similar properties but placed in different groups.
  5. He was not able to explain periodicity in properties of elements.
  6. Position of actinides and lanthanides is anamolous.
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