Question

Why was the system for classification of elements into triads discarded?

• A. It was possible to group similar elements.
• B. The atomic weight of the middle element was found generally to be the average of the other two.
• C. This method was soon discarded since only a few elements known at that time could be arranged in such triads.
• D. Elements were arranged in increasing order of their atomic weights.

Answer 1

The correct option is C

This method was soon discarded since only a few elements known at that time could be arranged in such triads.

Dobereiner grouped the elements in triads(groups of three elements), in such a way that the middle element of the triad had both atomic mass and properties roughly equal to the average of the other two elements of the triad. This method was soon discarded since only a few elements known at that time could be arranged in such triads.