Electron Cloud Copper

From the previous post "Most Penetrating X ray, Boron" dated 20 Jan 2018,

$A_x=1.1974*16.78*10^{-9}*\cfrac{0.1}{3.710}=5.41\text{e-10}$

If we assume that this is due to a particle of radius $a_{\psi}$ we have,

$a^2_{\psi}=\cfrac{A_x}{\pi}=1.7239\text{e-10}\,m$

$a_{\psi}=1.313\text{e-5}\,m$

This could be the size of the electron cloud of a copper atom.

This is wrong because a length $0.1\,m$ was used, it should be,

$A_x=1.1974*16.78*10^{-9}*\cfrac{1}{0.371}=5.41\text{e-8}$

where a length of $1\,m$ is used,

$a_{\psi}=1.313\text{e-4}\,m$

This is the effective size of the electric field around a copper atom and not the radius of the electron orbits around the nucleus, in the electron cloud.