Question

In a triad of $A,B,C$ elements, if the atomic masses of $A$ and $C$ respectively are $100$ and $200$, then the atomic mass of $B$ is:

• A. $300$
• B. $175$
• C. $125$
• D. $150$

Answer 1

The correct option is D $150$

According to Dobereiner's law of traid, the average of the masses of the first and the last element is equal to the atomic mass of the middle element. So, $\frac{100+200}{2}$ = 150. Hence, the atomic mass of $B$ is 150.

Hence, the correct option is $\text{D}$