Question

What is the electronic configuration of magnesium $\left({}_{12}^{24}Mg\right)$?

• A. 2, 9, 1
• B. 2, 8, 2
• C. 2, 8, 3
• D. 2, 6, 4

Answer 1

The correct option is B 2, 8, 2

The atomic number of magnesium is 12.
The maximum number of electrons that the K, L, and M shells can accommodate are 2, 8, and 18 respectively.
Filling of electrons in the shells takes place in the order: K, L, M.

Hence, the electronic configuration of magnesium is-
$$\begin{array}{cccc}\text{Shell}& \text{K}& \text{L}& \text{M}\\ \text{Number of electrons}& \text{2}& \text{8}& \text{2}\end{array}$$