Question

identify Dobereiners traids from the following groups of elements having similar chemical properties.
1. Mg(24.3), Ca(40.1), Sr(87.6)
2.S(32.1), Se(79.0), Te(127.6)
3.Be(9.0), Mg(24.3), Ca(40.1)

Answer 1

the answer is option 3

Answer 2

Dobereniers traids that is the artimetic mean of first and last elements of triads is equal to middle elements when we take three elements have same chemical properties
form 1
(Mg+Sr)/2=Ca
(24.3+87.6)/2=40.1
111.9/2=40.1
55.95=40.1
LHS ≠ RHS
so,this triads is wrong
2
(S+Te)/2=Se
(32.1+127.6)/2=79.0
159.7/2=79.0
79.85=79.0
It is approx right