I don't see anything wrong. I think it's confusing to write the numbers as you have. It's easier to see if you write it as
31Ga68-> 30Zn68 + 1e0
Your teacher may want you to write +1beta0 for the 1e0. A positron is a positive beta (electron) particle.
Write an equation for the positron emission of Ga-68 .
My answer: 68 31Ga -> 68 30Zn + 0 1e
What am I doing wrong?
2 answers
Looks like I just had to change it from a 1 to a +1. Thank you!