Question

Total number of electrons present in $48\text{g}$ of $M{g}^{2+}$ is:

• A. $2N_A$
• B. $20N_A$
• C. $23N_A$
• D. $24N_A$

Answer 1

The correct option is B $20N_A$

Electronic arrangement of $M{g}^{2+}:2,8$
In one mole of $M{g}^{2+}$ or $24\text{g}$ of $M{g}^{2+}$, $10N_A$ electrons are present.
So, in $48\text{g}$ of $M{g}^{2+}$, $20N_A$ electrons are present.