[LuminousNutria]

I'm in an elementary Biology class. I have an online worksheet that is asking me "How many electrons would be present in ¹⁹F^-?"
My assumption was that the 19 represented the atomic number, and therefore the amount of protons in the element. Since the amount of protons would be 19, I would need at least twenty electrons to have a negatively charged element. However, the highest possible answer was 14. So, I'm obviously making some false assumptions here.

What does ¹⁹F^- represent, and how can I derive the amount of electrons from it?

[Babcock_Hall]

What is the difference between atomic number and mass number?