This creates a magnesium ion with a charge of +2. Each element, when electrically neutral, has a number of electrons equal to its atomic number. A magnesium atom has an electron configuration whether it is negatively charged, neutral, or positively charged.electron configuration is not a fixed definition that only the first electron removed from a magnesium atom is one of the 4s2 electrons, leaving the electron configuration [ar]3d54s1.
orbital diagram for neutral magnesium atom