Question

Who was the founder of the law of triads?

Answer 1

The law of triads and the law of octaves were among the first methods for the classification of the elements into groups based on their properties. The value of the middle element in the triad would be exactly or nearly predicted by taking the arithmetic mean of the values for that property of the other two elements.

Complete step by step answer:
The Law of triads was founded by the German chemist Johann Wolfgang Dobereiner in the year 1817 when he observed that the properties of strontium were in between the properties of calcium and barium. By 1829, Dobereiner had found other groups of three elements and hence named these as ‘triads’, meaning three, with similarity in their properties. He also noted that some properties of elements like atomic weight and density followed a trend whereby the value of the middle element in the triad would be exactly or nearly predicted by taking the arithmetic mean of the values for that property of the other two elements.

Note:
The triad of elements predicted by him are as follows: “lithium, sodium, and potassium”, “calcium, strontium, and barium”, “ chlorine, bromine, and iodine”, “ sulphur, selenium, and tellurium”, and finally “ iron, cobalt, and nickel”. There are certain limitations to these law of triads which led to the acceptance to the Newland’s law of octaves:
-When new elements were identified this law became obsolete.
-Newly discovered elements did not fit into this law of triads.
-Only five triads of elements were discovered.
-Different other elements did not fit into this triad.