In ionic bonding, a metal element loses electrons. This is because metals have relatively low ionization energies, meaning it takes less energy to remove an electron from their outer shell.

When a metal atom loses electrons, it becomes a positively charged ion (also called a cation). The number of positive charges on the cation is equal to the number of electrons lost.

For example:

* Sodium (Na) has one electron in its outer shell. When it loses this electron, it becomes a sodium ion (Na+) with a +1 charge.

* Magnesium (Mg) has two electrons in its outer shell. When it loses these two electrons, it becomes a magnesium ion (Mg2+) with a +2 charge.