Chapter 16, Problem 18STP

To determine

To Explain: The concept of energy levels and their relation to the organization of elements on the periodic table.

Explanation of Solution

Introduction:

A nucleus of an atom consists of protons and neutrons. The electrons surround the nucleus in a region which is called electron cloud.

Electrons have different amounts of energy within an electron cloud. So, scientists placed electrons in the energy levels on the basis of their energy differences. Electrons present in the energy levels which are close to the nucleus have less energy than the electrons present in the energy levels away from the nucleus. These electrons are filled in a manner from inner to outer energy level. Those elements having the same number of electrons present in their outermost energy level are present in the same group. Hence, these energy levels organize the elements on the periodic table.

Conclusion:

Thus, the energy levels having different electrons organize the elements on the periodic table.