Question

For an atom ‘X’, K and L shells are completely filled. How many electrons will be present in it?

Answer 1

Maximum number of electrons in K shell is 2

Maximum number of electrons in L shell is 8

If these shells are completely filled, then

Total number of electron = Number of electron in K shell + Number of electron in L shell

Total number of electrons = 2 + 8 = 10
The atom is Neon which shells have completely filled.