Question

In triads, the average weight of the 1^st and the 3^rd element are equal to the second one.

(a) True

(b) False

This question was posed to me in my homework.

The question is from Genesis of Periodic Classification topic in division Classification of Elements and Periodicity in Properties of Chemistry – Class 11

Answer 1

Correct choice is (a) True

The explanation is: As per Dobereiner Triads, the above statement”. In triads, the weight the 2^nd element is about halfway between weights of 1^st and 3^rd elements.” For example, consider a triad of Li, Na, and K with atomic weight 7, 23 and 39 respectively.