Question

If an element has $2$ electrons in $\mathrm{L}$ shell, then what is its atomic number ?

Answer 1

Given:

Number of electrons in $\mathrm{L}$ shell$=2$

Fomula used:

Atomic number of the element$=$Number of electrons in the neutral atom

Find the total number of electrons in the atom of the element:

1. The electrons first enter the $\mathrm{K}$ shell and then go to the $\mathrm{L}$ shell.
2. The capacity of $\mathrm{K}$ shell is to hold maximum $2$ electrons. Thus, $\mathrm{K}$ shell has $2$ electrons.
3. And $\mathrm{L}$ shell has $2$ electrons.
4. Thus, total electrons in the atom of the element are $4$.

Find the atomic number of the element:

Atomic number of an element is equal to the number of electrons in the neutral atom of that element.

Thus,

Atomic number of the element$=4$

Thus, if an element has $2$ electrons in $\mathrm{L}$ shell, its atomic number is $4$