the modern periodic table has been evolved through the early attempts of dobereiner,newland and mendeleev. list one advantage and one limitation of all the three attempts
Answers
1. Dobereiner's advantage:
He arranged the known elements in increasing order of their atomic weight such that the atomic weight of the middle element is approximately average of remaining first and third elements atomic weights mostly known as Dobereinerlaw of traids
limitation:After improvement of spectroscopic study , his law did not remain stable
Newland's advantage:
He arranged the elements in increasing order of their atomic weights such that the eighth element properties are similar to first element properties.
limitation:
After discovery of inert gases the nineth element properties are similar to first element properties.
Mendeleev's advantage:
Atomic weight of elements we're determined with the help of mendeleev's formula ,it is
Atomic weight
=Valency×Equivalentweight
limitation:
Lanthanids and Actinids were not separated
1. Dobereiner's advantage:
He arranged the known elements in increasing order of their atomic weight such that the atomic weight of the middle element is approximately average of remaining first and third elements atomic weights mostly known as Dobereinerlaw of traids
limitation:After improvement of spectroscopic study , his law did not remain stable
Newland's advantage:
He arranged the elements in increasing order of their atomic weights such that the eighth element properties are similar to first element properties.
limitation:
After discovery of inert gases the nineth element properties are similar to first element properties.
Mendeleev's advantage:
Atomic weight of elements we're determined with the help of mendeleev's formula ,it is
Atomic weight
=Valency×Equivalentweight
limitation:
Lanthanids and Actinids were not separated