What happens to the valence electrons of a metal and a nonmetal when they form an ionic bond

Ionic bonds are also known as electrovalent bonds.

For ionic bonds to form, there is transfer of valence electrons from the metal to the non-metal. Metals are electropositive and would easily allow electrons to leave.

The goal of bonding is to achieve the octet configuration. An atom can lose or gain electrons to achieve this.

For example, to form NaCl, Na would loose its 1 valence electron. Cl would gain the Valence electron and complete it's octet with it.

This transfer of electron creates the ionic bond.

The metal which is less electronegative becomes positively charged. The non metal being more electronegative would become negatively charged.

Ionic compounds are polar compounds.