Which ion is formed when an atom of fluorine (f) gains one electron?

f–1
f–2
f+1
f+2

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 ion.

Thus, we can conclude that ion is formed when an atom of fluorine (F) gains one electron.