Question

a element that forms a triad with calcium and barium ​

Answer 1

Explanation:

(a) No, because all these elements do not have similar properties. Although the atomic mass of silicon (Si) is average of atomic masses of sodium (Na) and chlorine (Cl).

(b) Yes, because all the three elements similar properties and the mass of magnesium (Mg) is roughly the average of the atomic masses of Be and Ca.