Structure of th...

The Rutherford alpha ray scatlering experiment was one of the most significant experiment in the history of atomic structure. Alpha particles from a radioactive source were allowed to strike a thin gold foil. Alpha particles produce a tiny but visible flash of light when they strike a fluorescent screen. Few alpha particles were found to get deflected by  large angles and surprisingly a very few were even found to be back-scattered. 
The scattering of alpha particles by the nuclei of an atom can be modeled from coulombic forces of repulsion between the like charges. The scattering process can be treated statically in terms of the cross section for interaction with the nucleus which in considered to be a point charge $$Ze$$ for a detector at a specific angle with respect to be incident beam. The number of particles per unit area striking the detector, $$\displaystyle N(\theta )=\frac{N_{1}nLZ^{2}K^{2}e^{4}}{4r^{2}(KE)^{2}\sin ^{4}(\theta /2)}$$.
$$\displaystyle N_{1}$$ = Number of incident alpha particles 
$$n =$$ Atoms per unit volume in garget 
$$L =$$ Thickness of target
$$Z =$$ Atomic number of target
$$K =$$ Coulomb's constant 
$$e =$$ Electronic charge
$$r =$$ Target to detector distance 
$$KE =$$ Kinetic energy of alpha particles 
$$\displaystyle \theta =$$ Scattening angle 
Individual atoms of gold can be imagined as spheres of certain radii. Packing of these spheres in the following manner makes up the basic building block of all noble metals.