Question

select any three elements in a sequance from any group and calculate the arithmatic mean of the middle element and write whether it proves dobereiner's law of traid. Explain why or why not.​

Answer 1

Answer:

Let's take three elements i.e. Lithium (li) atomic mass 7 ,

Sodium (Na) atomic mass 23 and Potassium (k) atomic mass 39.

Now according to Dobereiner's three triads law

the average atomic mass of first and last elements is equal to middle one i.e. average atomic mass of lithium and potassium is equal to that of sodium.

let's prove it

atomic mass of sodium = average atomic mass of lithium and potassium

= 7+39/2

= 46/2

= 23

and 23 is atomic mass of sodium

Hence Dobereiner's law of three triads is proved.

Hope this will help you!