State and give one example for Dobereiner's law of triads and Newland's law of octaves.

Explanation

(1) Dobereiner law: `rarr` According to Dobereiner in a traid (3-elements) the atomic weight of the middle element is the arithmatic mean of the other two elements:
Eg: `{:(Ca,Sr,Ba),(40,88,137):} [(137+40)/(2)= (177)/(2)= 88.5]`
Newland.s law of octaves: According to Newlands, the elements arranged in the increasing order of atomic weights noticed that every eight element had properties similar to the first element. This relationship was just like every eight note that resembles the first in octaves of music.