Question

Which of the following groups form the Dobereiner’s triad?

• A. N, P, As
• B. F, Cl, Br
• C. Ca, Sr, Ba
• D. Be, Mg, Ca

Hint:

Dobereiner’s triads were an early attempt at classifying elements, which later led to the development of the modern periodic table.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Dobereiner’s triads were groups of three elements with similar properties in which the atomic weight of the middle element is nearly the average of the other two. Step 2: Detailed Explanation:
The group Ca, Sr, Ba forms a Dobereiner’s triad: \[ \text{Atomic weight of Sr} \approx \frac{\text{Atomic weight of Ca + Atomic weight of Ba}}{2} \] This relationship holds true for alkaline earth metals Ca, Sr, and Ba.
Step 3: Final Answer:
The correct Dobereiner’s triad is Ca, Sr, Ba.