Measurements from repeated decays of identical unstable nuclei give the following results.
| Property of the nucleus | Before the decay | After the decay |
|---|---|---|
| Number of protons | 27 | 28 |
| Number of neutrons | 33 | 32 |
| Property of the emitted particle | Value |
|---|---|
| Mass number | 0 |
| Charge | -1 |
A student claims that the emitted particle was an electron that escaped from an electron shell.
Explain why the measurements do not support the student's claim.