Chemistry 1 - Types of Radioactive Decay

Explanation:

The reaction expression is given as:

           ⁴⁰₁₈ Ar   →   X  +  ⁰₁B  

To solve this problem, we must bear in mind that both mass number and atomic number must be conserved.

 So;

For the mass number:

               40  = A + 0

                 A  = 40

For atomic number:

                 18  = Z + 1

                  Z = 18 - 1  = 17

An atom is identifiable by the atomic number. Since the atomic number of X is 17 then it is Cl, chlorine