Question

what is the similarities as well as differences betweenDobereiners triads andNewlands Law of Octaves

Answer 1

Similarities:

1. Both classifications grouped elements on basis of similar properties.
2. In both the classifications, certain elements like Li, Na, K and Ca, Sr, and Cl, Br, I are grouped together.

Differences :

1. Dobereiner’s elements were grouped in three’s while the Newland classification found that when elements are arranged with increasing atomic mass, every 8^th element was similar to the first one in its properties. The periodic table was divided into 7 groups.
2. In the triads, the atomic mass of the middle element was the average atomic mass of the other two elements. This was not seen in the Newland’s table.
3. Only very few elements could be arranged in the triads form while 56 elements could be arranged in the Newland’s table.