Table 10.3 shows that the van der Waals $b$ parameter has units of $\mathrm{L} / \mathrm{mol} .$ This implies that we can calculate the size of atoms or molecules from $b$ . Using the value of $b$ for $\mathrm{Xe},$ calculate the radius of a Xe atom and compare it to the value found in Figure 7.7 , that is, 1.40$\hat{\mathrm{A}}$ . Recall that the volume of a sphere is $(4 / 3) \pi r^{3}$ .