Question

plz ans. Me
ONE Advantageand disadvantage of doberenier . Newland and mendeleev

Answer 1

advantage:dobernier was able to show that atomic mass was a fundamental property of elements
limitations:he could show only 3 triads

advantage:he was the one to achieve the concept of periodicity
limitation:he placed some dissimilar elements in the same group such as Au was placed with alkali metals

advantage:he was able to predict some new elements such as gallium
limitation:there were some anomalous pair of elements such as Te was placed before I

Answer 2

German chemist Johann Wolfgang Döberenier is 1817 first observed elements with significant relationship between Atomic Weights and Properties. This was the advantage. The limitation was that he could identity only 3 triads.
In 1865, John Newlands' ,an English chemist formulated his Law of Octaves.He found that every eighth element starting from a point has similar properties. But it was only applicable up to Calcium.
In 1869, Dmitri Ivanovich Mendeleev, a Russian chemist proposed his periodic law.His law made Systematic Study of Elements easier,as the properties of a given compound can be easily known by knowing the properties of elements. The limitation was,According to him properties of elements was based on their atomic masses but as we know the isotope of a given element is also havin' different atomic masses,so a different slot should be formed for them.But Mendeleev didn't do that.
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