Answer: Option (a) is the correct answer.
Explanation:
When an atom or element gains an electron then the atom acquires a negative charge whereas when an atom or element loses an electron then it acquires a positive charge.
for example, atomic number of fluorine is 9 and when it gains one electron then fluorine atom acquires a negative charge. Hence, neutral atom of fluorine changes into [tex]F^{-1}[/tex] ion.
Thus, we can conclude that [tex]F^{-1}[/tex] ion is formed when an atom of fluorine (F) gains one electron.
