Why was Mandaleev's periodic table discarded?
- Anamolous position of Hydrogen(It behaves both as metals-non-metals)
- They were arranged in position of increasing atomic masses .But there were some anamolies.Like argon was placed before potassium based on properties.
- As Mass was chosen as the basis positioning of isotopes was anamolous.
- 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.
- He was not able to explain periodicity in properties of elements.
- Position of actinides and lanthanides is anamolous.