Compare dobereiner’s triads to the modern periodic table. what aspects of his idea agreed with the modern table and what aspects did not

In  Dobereiner’s triads, elements were placed :

According to increasing order of their atomic masses.Into groups which have similar chemical and physical properties.In each group there were three elements.

In Modern periodic table, elements are placed:

According to increasing order of their atomic numbers.Into groups and these groups are assigned according to the numbers of valence electrons present in their valence shell.

Aspects of Dobereiner’s triads agreed with the modern periodic table

Element of the same group will have similar chemical and physical properties.

Disagreement with the modern periodic table.

Not all groups obeyed law of triads.On the basis of properties all known elements could not be classified into groups of triads.

They carry out the exchange of gases as we breathe ( oxygen and carbon dioxide).