`Na^(+)` has completely filled K and L shells. Explain.

Explanation

A sodium ion, `Na^(+)`, has 10 electrons in it. Now, the maximum capacity of K shell is 2 electrons and that of L shell is 8 electrons. Taken together, the maximum capacity of K and L shell is `2 +8 = 10` electrons. A sodium ion `Na^(+)` has completely filled K and L shells because its 10 electrons can completely fill up K and L shells.