Particle P is neutral, with an atomic number of $18$ and a mass number of $40$. Particle Q has an atomic number of $19$, a mass number of $40$ and a charge of +1. Which statement is correct?
- AThey are isotopes of the same element.
- BThey are both ions.
- CQ has more neutrons than P.
- DThey have the same number of electrons in their outer shell.