$${\mathrm{^19}F}$$

Here:

* 19: This is the mass number, which represents the total number of protons and neutrons in the nucleus of a fluorine atom. Fluorine has a mass number of 19, which means its nucleus contains 19 protons and neutrons combined.

* F: This is the chemical symbol for fluorine, denoting the element itself.

* 9: The number of protons in fluorine's nucleus. This number is known as the atomic number.