The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase.
The modern periodic table has a lot to say about the chemical elements, besides the atomic number, atomic weight, and symbol of the identified elements. For example, chemical elements falling in the same group share common properties, which are different from other groups. Also, go through the periodic table trends and you will come to know a regular pattern in the alteration of physical and chemical properties of elements, as you go from left to right, from top to down direction, and vice versa.
Explanation:
I hope this gives an idea to your question - Good luck ^w
