Question

P,Q and R are the elements of a dobereiner's trade arranged in the increasing order of their atomic masses.If the atomic mass of P and R are 7 and 49 what would be the atomic mass of Q? Does the traid can exist in newlands octaves
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Answer 1

Answer:

For atomic mass of Q take the average of P and R

7+49 /2 = 28

Yes. Only one triad of Dobereiner's triads exists in the columns of Newlands' octaves.For example, the second column of Newlands' classification has the elements lithium (Li), sodium (Na) and Potassium (K), which is a part of a Dobereiner’s triad.