The symbols of two ions are displayed, $^{19}_{9}\text{F}^-$ and $^{21}_{11}\text{Na}^+$. Which statement is correct?
- AThe fluoride ion contains more electrons than the sodium ion.
- BThe sodium ion contains more neutrons than the fluoride ion.
- CThe two ions contain the same number of electrons as each other.
- DThe two ions contain the same number of protons as each other.