A teacher gives a class the data for an ion.
| Atomic number | Mass number | Relative charge |
|---|---|---|
| 19 | 41 | +1 |
Four students each work out the numbers of electrons and neutrons in the ion.
| Student | Number of electrons | Number of neutrons |
|---|---|---|
| P | 19 | 22 |
| Q | 18 | 41 |
| R | 18 | 22 |
| S | 20 | 21 |
Which student is correct?
student S
student P
student Q
student R