The elements in each period of the periodic table have the same number of electron shells. To determine the number of electron shells in a period, you can count the number of elements in that period. Each new period starts with the filling of a new electron shell. For example, the first period (Period 1) contains only two elements, hydrogen and helium, which have one and two electron shells, respectively. The second period (Period 2) contains eight elements, which have two electron shells, and so on.
The elements in each period have the same number of electron shells.
