Question

1) (A, B, C) is a Dobereiner's triad. Complete the following chart and give reason for the answer :
Element
A
B
C
Atomic Mass
10.08
12.01 +​

Answer 1

Answer:

Correct option is

C

23

According to Dobreiner's triad, the atomic mass of the central element (B) is the arithmetic mean of the atomic masses of the other two elements (A and C ).

Given that: A=7, B=15

Let the mass of C be MC.

MB=2MA+MC

15=27+Mc

⇒MC=23.