Question

A 'B' and 'C' are three elements that form a triad. If the atomic weight of 'A' is 7 and that of
group
'C' is 39 then according to Döbereiner's rule of triads what will be the atomic weight of "B"?
Li Be BCN
OF
The figure shows a part of the periodic table:​

Answer 1

Answer:

23

Explanation:

hope it helps you.......

Answer 2

Answer:

the weight of middle element will be 42.5