Question

In Dobereiner’s triads Li, Na, K, the atomic masses of Lithium and Potassium are 6.9 and 39.1 respectively, then what will be the atomic mass of sodium?

Answer 1

According to Doberiner’s triads, the average atomic mass of two elements is the atomic mass of the third element in a series Na and K.
Average atomic mass of sodium = `"Atomic mass of Li and K"/2`

`= (6.9+39.1)/2`

= `46/2`

= 23