Question

Give two differences between magnesium ion and magnesium atom ?

Answer 1

$M{g}^{2+}$ is a Mg atom that now has the same number of electrons as a noble gas.

Mg is an atom of the element magnesium. It is electrically neutral, with 2 electrons in its outer (valence) shell.

$M{g}^{2+}$ is an ion of magnesium that has given up its 2 outer shell electrons.