Answer: The atomic number and mass number of the new element formed is 89 and 228 respectively.
Explanation:
Beta decay is defined as the process in which beta particle is emitted. In this process, a neutron gets converted to a proton and an electron. The released beta particle is also known as electron.
In this process, the atomic number of the daughter nuclei gets increased by a factor of 1 but the mass number remains the same.
[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta[/tex]
The chemical equation for the beta decay of Ra-228 follows:
[tex]_{88}^{228}\tyextrm{Ra}\rightarrow _{89}^{228}\textrm{Ac}+_{-1}^0\beta[/tex]
Hence, the atomic number and mass number of the new element formed is 89 and 228 respectively.