Question

Which of the following triads is NOT a Dobereiner's triad?

1. (i) Li, Na. K
2. (ii) Ca, Sr, Ba
3. (iii) N, P, Sb
4. (iv) Cl, Br, I

• A. None of these
• B. 1, 4
• C. 1, 2
• D. 3 only

Answer 1

Answer:

D. 3 only

• Dobereiner's triads are groups of three elements with similar chemical properties, where the atomic weight of the middle element is approximately the average of the atomic weights of the other two elements.

• Dobereiner's triads were groups of elements with similar properties that were identified by the German chemist Johann Wolfgang Dobereiner.

• He observed that groups of three elements (triads) could be formed in which all the elements shared similar physical and chemical properties.