Chapter 7, Problem 1RQ

To determine

The reason why it is said that an atom is mostly composed of empty space.

Answer to Problem 1RQ

An atom is composed with nucleus and electrons in a surrounding cloud. Thus inside of an atom is empty

Explanation of Solution

An atom is made up of electron proton and neutron. The proton and neutron together formed the nucleus of the atom. And the electron is in a surrounding cloud.

As an example, considering the simplest type atom hydrogen which is having one proton and one electron. The proton is having diameter of about $1.7\times {10}^{-6}\text{nm}$ and electron cloud is having diameter of about $0.24\text{nm}$.

The volume of nucleus is in the range of ${10}^{-18}{\text{nm}}^3$ whereas the total volume of the entire hydrogen is in the range of ${10}^{-3}{\text{nm}}^3$. Thus, by comparing the total volume of the hydrogen to the volume of the nucleus is ${10}^{-15}$ times greater. Hence, inside of an atom is almost empty. For the volume of the other atom, hydrogen atom volume is keeping as standard value. Thus, it is clear that the most of the inner space of an atom is empty.