Answer: Elements that belong to the same period have same number of energy levels.
Step-by-step explanation:
In a periodic table, elements are distributed in rows and columns.
Rows are known as the Periods in a periodic table and columns are known as Groups in the periodic table.
There are 7 Periods and 18 Groups in a periodic table.
In a groups, the energy level increases as we move down but in a period, energy level remain the same as we move from left to right. Elements belonging to the same group show similar chemical properties while that belonging to the same period does not show any similar chemical property.
Hence, elements that belong to the same period have same number of energy levels in a periodic table.