Question

What do u mean by Doberiener's Triad.? explain

Answer 1

a German scientist dobereiner said that properties of elements related to their atomic mass . he made a group of three elements having same chemical properties.and called them triads.
here atomic mass of middle element was approximately equal to the mean of atomic masses of other two elements.
e.g..Ca,Sr,Ba
hope this answer helps you.
Mark me as brain list ☺

Answer 2

According to Dobereiner, all elements occurred in groups of three, when arranged in increasing order of atomic masses. He referred to these groups as triads. ...Dobereiner's law of triadsstates that, the atomic mass of the middle element of a triad is the arithmetic mean of the atomic masses of the other two elements.


OR


This dates back to the pre periodic table era. Many of the elements were known and their atomic masses were calculated. Scientists were trying to sort elements w.r.t to the known propertierties. Johann Wolfgang Döbereiner noticed the sets of three elements with quantifiable atomic weight and densities.
In 1829, the German chemist Johann Wolfgang Döbereiner noted that there were groups of three elements (hence "triads") which had similar physical properties. He also noted that some quantifiable properties of elements (e.g. atomic weight and density) in a triad followed a trend whereby the value of the middle element in the triad would be exactly or near exactly predicted by taking the arithmetic mean of values for that property of the other two elements.


H҉ O҉ P҉ E҉  
I҉ T҉  
H҉ E҉ L҉ P҉ S҉
  Y҉ O҉ U҉