Ionic Bonding

1. Instance: NaCl.
2. Na (Z = 11) gives up the outermost shell electron of it to Cl (Z=17) atom, so the crystal is build up of ions with the electronic structures of the inert atoms Ne and Ar.
3. Note: the ions comprise net electric charges after the electron exchange → Na⁺ ion has a net positive charge, comprising lost an electron, and CI^- ion has a net negative charge, having achieved an electron.
4. So, an electrostatic attractive force is established, and the balance is arrived at when this equals the net repulsive force.

5. Note: all the electrons are bound tightly to the atom.

6. Because there are no loosely bound electrons to participate in current flow → NaCl is a good insulator.