Fluorine atom contains 7 electrons in the outermost shell. But its valency is '1'. Explain.

Explanation

1) Valency is the number of electrons present in the outer most orbit of an atom.
2) The distribution of electrons in fluorine (atomic number 9) is 2, 7.
3) Hence the valency of fluorine could be 7.
4) But it is easier to fluorine to gain one electron for becoming octet.
5) Hence its valency is determined by subtracting seven electrons from 8 and which gives you a valency '1' for fluorine.