Neon has electronic configuration of  2,8

\(_3\)Li\(^+\) has electronic configuration of  2 (because the + sign shows it has given out one electron from the initial 2, 1, and now has 2 with only one shell)

\(_9\)F\(^-\) has electronic configuration of  2, 8 (because the - sign shows it has accepted one electron and now the initial 2, 7, now becomes 2,8 with only 2 shells)

\(_{17}\)CI\(^-\) has electronic configuration of  2,8,8 (because the - sign shows it has accepted one electron and now the initial 2,8, 7,now becomes 2,8,8 with only 3 shells)

\(_{19}\)K\(^+\) has electronic configuration of  2,8,8(because the - sign shows it has given out one electron and now the initial 2,8,8,1 now becomes 2,8,8 with only 3 shells)

Among all the options above, the only one that has the same number of electrons (Isoelectronic) with Neon (2,8) is \(_9\)F\(^-\) (2,8)