Question

The electronic configuration of Fluoride ion is the same as that of a neon atom. What is the difference between the two?

Answer 1

fluoride ion has a negative charge on it, where as neon atom is neutral. fluoride ion can still react and lose that electron , where as a noble gas will not react.

Answer 2

The electronic configuration of any atom or ion indicates the "number of electrons" in an atom or ion but it does not give any information about number of protons.

For fluoride ion, the valence shell electronic configuration is $2 s^{2}, \ 2 p^{6}$ which is same as Neon atom. But fluoride ion has -1 charge and has 9 protons in its nucleus.

On the contrary, neon atom is neutral means it has zero charge and has 10 protons in its nucleus, so the "atomic number" of neon is 10 whereas the "atomic number" of fluorine is 9.