It was assumed by Newlands that only :

What were the limitations of Dobereiner's classification?

It was found that the law of octaves was applicable only up to:

Can the following groups of elements be classified as Dobereiner's triad?
$(a)$ $Na, Si, Cl$
$(b)$ $Be, Mg, Ca$
Atomic mass of $Be = 9, Na = 23, Mg = 24, Si = 28, Cl = 35, Ca = 40$. Explain by giving reasons.

Write true or false for the statement: It was assumed by Newlands that only $63$ elements existed in nature and no more elements would be discovered in the future.

Did Dobereiner's triads also exist in the columns of Newlands' Octaves? Compare and find out.