Question

Complete the chart:

Name of the element	Symbol of the element	Atomic number	Mass number	No. of protons	No. of electrons	No. of neutrons	Electronic configuration
Magnesium		12		12		12	K	L	M

Answer 1

Identify the symbol of Magnesium:

The chemical symbol of Magnesium is $\mathrm{Mg}$.

Calculate the number of electrons in Magnesium:

In a neutral atom,

Number of electrons$=$Atomic number

Thus,

Number of electrons$=12$

Calculate themass number of Magnesium:

Mass number$=$Number of protons$+$Number of neutrons

Thus,

Mass number$=12+12=24$

Write the electronic configuration for Sodium:

1. The number of electrons in Magnesium are $11$.
2. The first $\mathrm{K}$ shell occupies $2$ electrons, second $\mathrm{L}$ shell occupies $8$ electrons and the remaining $2$ electrons go to the third $\mathrm{M}$ shell.
3. Thus, the electronic configuration of Magnesium is $\mathrm{K}=2$, $\mathrm{L}=8$ and $\mathrm{M}=2$.

Thus, the chart is as follows:

Name of the element	Symbol of the element	Atomic number	Mass number	No. of protons	No. of electrons	No. of neutrons	Electronic configuration
Magnesium	$\mathrm{Mg}$	12	24	12	12	12	$\mathrm{K}=2$	$\mathrm{L}=8$	$\mathrm{M}=2$