Radius of a nucleus

Definition

The radius of a nucleus is the distance from the center of the nucleus to its outer edge. It is typically measured in femtometers (fm), where 1 fm = $10^{-15}$ meters.

5 Must Know Facts For Your Next Test

1. The radius of a nucleus can be approximated using the formula $R = R_0 A^{1/3}$, where $R_0 \approx 1.2$ fm and $A$ is the mass number.
2. Nuclear radii are much smaller than atomic radii, which are on the order of angstroms ($10^{-10}$ meters).
3. The nuclear force that binds protons and neutrons operates over very short ranges, comparable to nuclear radii.
4. Nuclear density is nearly constant across different nuclei because volume increases with mass number as $A$, while radius increases as $A^{1/3}$.
5. The concept of a nuclear radius helps in understanding phenomena like nuclear binding energy and stability.

Review Questions

• What formula is used to approximate the radius of a nucleus?
• How does the nuclear force relate to the size of the nucleus?
• Why is it significant that nuclear density remains nearly constant across different nuclei?

Related terms

Mass Number (A): The total number of protons and neutrons in an atomic nucleus.

Femtometer (fm): A unit of length equal to $10^{-15}$ meters, commonly used to measure nuclear dimensions.

Nuclear Binding Energy: The energy required to split a nucleus into its constituent protons and neutrons.