Here's why:
* Fluorine's electron configuration: Fluorine has 9 electrons, with the configuration 2, 7. This means it has 7 electrons in its outer shell, making it highly reactive and eager to gain an electron to achieve a stable octet (8 electrons) in its outer shell.
* Gaining an electron: When fluorine gains an electron, it fills its outer shell, becoming a negatively charged ion called a fluoride ion (F-).
The fluoride ion is much more stable than the neutral fluorine atom, as it now has a full outer shell. This stability is the driving force behind fluorine's reactivity and its tendency to form ionic bonds.
