Question

If two members of Dobereiner’s triad are calcium and barium, then the third member of the

triad is ……………​

Answer 1

Answer:

According to Dobereiner, the atomic mass of the middle element was nearly equal to the arithmetic mean of the other two. Therefore, the atomic mass of the third element is =

2

31+121.75

= 76.37 which is nearly equal to the atomic mass of arsenic.