Ions, unlike normal atoms, have a charge (positive or negative)

When atoms lose or gain atoms they are trying to gain a full outer shell and become stable

Metals lose electrons so become positively charged

Non metals lose electrons and become negatively charged

When a metal and a non metal react, the metal becomes positively charged while the non metal becomes negatively charged. The oppositely charged ions are strongly attracted by electrostatic forces.

Ionic bonding happens when there is a transfer of electrons

The metal gives up 1-3 electrons and the non metal gains those electrons

You can demonstrate ionic bonding with a dot and cross diagram

Ionic compounds are in a giant ionic lattice

the ions form a closely packed regular lattice, with strong electrostatic forces of attraction between the oppositely charged ions

a ball and stick diagram is often used to show the giant ionic lattice, however there aren't gaps between the ions and the sizes of the ions aren't relative

High melting/boiling points due to strong bonds between the ions

When dissolved or melted the ions can move so they carry an electric current