Atoms and Nuclei

A nucleus has:
Radius R=R0A1∕3,
where R0≈1.2×10−15m
Each nucleon (proton or neutron) has a mass mn≈1.67×10−27kg
Step 2: Estimate the number of nucleons per unit volume
For nuclear matter, the volume per nucleon is roughly the volume of a sphere of radius R0 :
V‌per nucleon ‌‌‌≈‌

4

3

πR03
V‌per nucleon ‌‌‌≈‌

4

3

π(1.2×10−15)3≈7.2×10−45m3
Hence, number density of nucleons:
n=‌

1

V‌per nucleon ‌

≈‌

1

7.2×10−45

≈1.4×1044m−3
Step 3: Compute the mass density
ρ=n×mn=(1.4×1044)(1.67×10−27)≈2.3×1017kgm−3
Density of nuclear matter ∼1017kgm−3