Elements in one row of the periodic table have the same energy levels. A row on the periodic table is the horizontal arrangement of elements. These rows are called periods.
There are 7 periods on the periodic table.
Each elements on a period begins with an atom having one valence electrons and then ending with completely filled orbitals.
Elements in the same period are known to have the same electronic shells which is the energy level.
The principal quantum number of their electrons is the same.
