Question

Identify the correct electronic configuration for ${\text{Mg}}^{2+}$ ion.

• A. 2, 8, 2
• B. 2, 10
• C. 3, 7
• D. 2, 8

Answer 1

The correct option is D 2, 8

Atomic number of magnesium atom = 12.
It has 12 protons, 12 electrons and 12 neutrons.
Electronic configuration is the distribution of electrons in the shells.
Maximum number of electrons that a shell can accomodate is given by ${\text{2n}}^2$, where 'n' denotes the shell number. The electronic configuration of magnesium atom is 2, 8, 2. Magnesium atom loses 2 electrons from its outermost shell to form ${\text{Mg}}^{2+}$ ion. Hence, ${\text{Mg}}^{2+}$ ion has total 10 electrons. Thus, electronic configuration of ${\text{Mg}}^{2+}$ ion is 2, 8.