Can the following groups of elements be classified as Dobereiner's triad?
a) Na, Si, Cl
b) Be, Mg, Ca
The atomic mass of Be 9; Na 23; Mg 24; Si 28; Cl 35; Ca 40
Explain by giving reasons.
Dobereiner's triad:
Dobereiner's triad made a group of three elements and arranged them in the order of increasing atomic masses. He observed that the average sum of the other two elements is equal to the atomic mass of the third element.
(a) No, these elements cannot be classified as Dobereiner's triads despite the fact that silicon has an atomic mass equal to the average sum of the atomic mass of sodium and chlorine, these elements do not have similar properties.
(b) The triad is possible as all the elements have similar properties and also the average atomic mass of Beryllium and Calcium is equal to the mass of Magnesium.