Question

Chlorine, bromine and iodine form a Dobereiner's triad. Chlorine has atomic mass 35.5 and iodine has atomic mass 126.9. Predict the atomic mass of bromine.

Answer 1

Dobereiner's triads- It states that the atomic mass of middle element in doberiener's triad is exactly or nearly the arithmetic mean of the atomic masses of other two elements.

$\therefore AtomicmassofBromine=\frac{\left(Atomicmassofchlorine\right)+\left(AtomicmassofIodine\right)}{2}$

$⟹$ Atomic mass of Bromine $=\frac{35.5+126.9}{2}$

$⟹$ Atomic mass of Bromine $=81.2$