Final answer:
The limitations of Dobereiner's triads included the inability to group all known elements into triads, the absence of a comprehensive arrangement of elements, and the failure to account for elements that did not fit into any triads.
Step-by-step explanation:
The limitations of Dobereiner's triads were that not all known elements could be grouped into triads, and there were gaps in the triads he proposed. For example, there was no known element that could be grouped with oxygen and sulfur to form a triad. Additionally, Dobereiner's triads did not account for the full range of chemical properties and behaviors exhibited by the elements.
One of the shortcomings of the triad system was that it did not provide a comprehensive arrangement of all the elements and did not account for elements that were discovered after Dobereiner's time. Furthermore, the triad system did not provide a clear pattern or explanation for the similarities and differences in properties among elements.
Another limitation of the triad system was that it did not account for elements that did not fit into any triads, such as the noble gases. These elements have very different properties compared to the elements in the triads. Therefore, the triad system was not able to fully explain or predict the behavior of all the elements.