When a nucleus undergoes a radioactive decay it produces three types of radioactivity, radioactivity.

To show the radioactive decay equation of the 3 products:

where

X is the chemical element given, A is the atomic weight and B is the atomic number which comprises of mass of proton and electron. The value of denotes alpha, beta particles and gamma rays respectively.

As you can see from the decay formula, while after undergoing alpha and beta decay the electronic configuration of the nucleus changes while for the gamma decay it stays the same. Therefore, the electronic configuration will change for the and but not for the radiation.