Question

question 7 points 2
what is the daughter nucleus of pt - 199 after a beta decay?
au - 198
au - 200
pt - 200
au - 199

Explanation:

Step1: Recall beta decay equation

In beta decay, \(_{Z}^{A}X
ightarrow _{Z + 1}^{A}Y+\beta^{-}+\bar{
u}\) (where \(X\) is parent nucleus, \(Y\) is daughter nucleus, \(\beta^{-}\) is electron, \(\bar{
u}\) is antineutrino). For Pt - 199, \(Z_{Pt}=78\), \(A = 199\).

Step2: Calculate daughter nucleus

After beta decay, \(Z_{daughter}=Z_{Pt}+ 1=78 + 1=79\) (79 is atomic number of Au), \(A_{daughter}=A_{Pt}=199\).

Answer:

Au - 199