For nuclei with A > 20 that are not in highly excited states, the protons and neutrons are generally clustered together in an approximately spherical volume whose radius, r, has been empirically found to scale as A^1/3. Specifically, 

r = (1.2 x 10^-5 m) A^1/3

Compare the sizes of the following isotopes to the size of the first Bohr orbit in hydrogen computed in Example 10.3 to be 5.29 x 10^-11 m: 

(a) Aluminum-27; 

(b) argon-40;

(c) Copper-63;

(d) Cesium-134;

(e) Bismuth-211.