Question

Write the beta decay equation for the following isotope: 91 38 Sr? Please write out steps

Answer 1

Answer:

$\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}Y$

Explanation:

The unbalanced nuclear equation is

$\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e \, + \, ?$

Let's write the question mark as a nuclear symbol.

$\rm _{38}^{91}Se} \longrightarrow \, _{-1}^{0}e \, + \, _{Z}^{A}X$

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.  

Then

98 =  0 + A, so A =  98 -  0 = 98, and

38 = -1 + Z, so Z  = 38 + 1 = 39

Then, your nuclear equation becomes

$\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}X$

Element 39 is yttrium, so the balanced nuclear equation is

$\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}Y$