How does electronic configuration of atoms change in the period within increase in the atomic number

How does electronic configuration of atoms change in the period within

1.	How does electronic configuration of atoms change in the period within increase in the atomic number
Answer» Because there are dozens of different energy shell energy levels. While there are only 4 shells, S, P, D, and F, you can have each in a minimum of 8 different levels. The higher the atomic #, the more electrons, and the more shells in use. It\'s that simple. Why is Ca 1s2 2s2 2p6 3s2 3p6 4s2? Because 2+2+6+2+6+2 = 20, Ca\'s atomic #, that\'s why!