After ionic bonding, sodium (Na) became isoelectronic with neon (Ne) while chlorine became isoelectronic with argon (Ar). This means both sodium and chlorine attained stability. Isoelectronic means an atom or ion has the same number of electrons as another atom or ion. In this case, sodium (Na) acquired the same electronic configuration with neon (Ne), and chlorine acquired the same configuration with that of argon (Ar). Therefore, both of them became stable. Guide Questions: Q9. What kind of element forms cation after ionic bonding? - Answer: Metals-