Question

Calculate the maximum number of electrons which can be present in a shell having principal quantum number 3.

• A. 8
• B. 4
• C. 16
• D. 18

Answer 1

The correct option is D 18

Maximum number of electrons present in a shell is given by $2n^2$.
where n = principal quantum number
So, for n = 3, maximum number of electrons present is $2.\left(3^2\right)$ = 18.