If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

Explanation

The maximum number of electrons present in a shell `= 2n^2`
where n = shell number
Value of n for K shell = 1
` therefore ` Maximum number of electrons in K shell
`= 2n^2 = 2(1)^2 = 2`
Value of n for L shell = 2
` therefore ` Maximum number of electrons in L shell
`= 2(2)^2 = 8`
Thus, total no. of electrons = 2 + 8 = 10