Question

(a)Chlorine, bromine and iodine form a Dobereiner’s triad. The atomic masses of

chlorine and iodine are 35.5 and 126.9 respectively. Predict the atomic mass of bromine.

(b) Lithium, sodium and potassium form a Dobereiner’s triad. The atomic masses of

lithium and potassium are 7 and 39 respectively. Predict the atomic mass of sodium.​

Answer 1

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a)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.

∴AtomicmassofBromine= 2

(Atomicmassofchlorine)+(AtomicmassofIodine)

⟹ Atomic mass of Bromine =2

35.5+126.9

⟹ Atomic mass of Bromine =81.2

Answer 2

Answer:

the answer is 81.2