Question

what is the missing particle?
34 15 p → ? + 34 16 s
4 2 he -1 0 e 0 -1 e

Explanation:

Step1: Apply mass - number conservation

The mass - number of the reactant ($^{34}_{15}P$) is 34. The mass - number of one of the products ($^{34}_{16}S$) is 34. So the mass - number of the missing particle must be 0.

Step2: Apply atomic - number conservation

The atomic - number of the reactant ($^{34}_{15}P$) is 15. The atomic - number of the product ($^{34}_{16}S$) is 16. To balance the atomic - number, the atomic - number of the missing particle must be - 1.

Step3: Identify the particle

A particle with mass - number 0 and atomic - number - 1 is a beta particle ($_{-1}^0e$).

Answer:

$_{-1}^0e$