To help you figure out the answer, here's some information about fluorine's electrons:

* Atomic number: The atomic number tells us the number of protons in an atom. Since atoms are electrically neutral, the number of protons also equals the number of electrons. Fluorine has 9 protons, so it also has 9 electrons.

* Mass number: The mass number is the total number of protons and neutrons in an atom. Since fluorine has a mass number of 19 and 9 protons, it has 10 neutrons (19 - 9 = 10).

* Electron shells: Electrons in an atom occupy specific energy levels called shells. Fluorine has 2 electrons in the first shell and 7 electrons in the second shell.

Please clarify your question:

* Are you asking how many electrons fluorine needs to gain to become a stable ion? Fluorine typically gains one electron to become a fluoride ion (F-), completing its outermost shell and achieving a stable octet.

* Are you asking how many electrons fluorine needs to share to form covalent bonds? Fluorine often forms single covalent bonds with other atoms, sharing one electron with each atom it bonds to.

Let me know what you want to know, and I can give you a more precise answer!