In two alkaline earth metal salts, one gives apple green and other gives brick red in flame test. The sum of atomic number of those alkaline earth metals is x. Then the value of ‘x’ is ____

The flame colors of the alkaline earth metal salts in the Bunsen burner are as shown: Calcium gives Brick red color. Strontium gives Crimson color. Barium gives Apple green color. The electrons can be easily excited to higher energy levels. This results in characteristic color during de-excitation of electrons.

Atomic number of Barium is 56 and calcium is 20. 

56+20=76, means value of X is 76.