How is electron movement related to the bonding in sodium chloride?

The electron movement towards the chlorine atoms mostly lead to ionic bonding in sodium chloride.

Explanation

Sodium chloride is an ionic bond compound.

Ionic bonding usually occurs between elements having high difference in their electronegativities.

Here chlorine is highly electronegative compared with sodium.

The atomic number of sodium is 11 and the atomic number of chlorine is 17. So the electronic configuration of sodium is [Ne] 3s1 and the electronic configuration of chlorine is [Ne] 3s23p5.

So from this, it can be confirmed that sodium has extra one electron in the 3s shell which is ready to combine with another element.

The one electron in the outermost shell of sodium is loosely bonded with the nucleus and it has a tendency to bind with other element to attain a stable state.

So sodium is electropositive in nature and its charge is Na+. Similarly the electronic configuration of chlorine indicates that it requires an electron to stabilize itself on the basis of octet rule, i.e, the outermost shell will be filled with 8 electrons when one electron will be added in chlorine.

So chlorine has the tendency to attract electrons and hence denoted as Cl-.

So the one loosely bond electron in the outermost shell of Na transfers to the outermost shell of Cl, stabilizing both the elements and forming a compound of NaCl by ionic bonding between them.