Question

The atomic number of fluorine is 9. Explain the formation of fluoride ion.

Answer 1

Fluorine in its elemental state is a highly electronegative element in the periodic table. Fluorine atom has an electronic configuration of $1s^2$ $2s^2$ $2p^5$. So, it is one electron less to form a stable octate or to attain a noble gas configuration. So, Fluorine atom gains one electron to change to flouride anion $\left(F^{-}\right)$ to attain stable octate. This formation of fluoride releases energy so, formula of fluoride ion is exothermic.