Rutherford’s Atomic Model

Rutherford’s Atomic Model – The Nuclear Atom:

In 1909 Rutherford performed their historic Alpha Particle-Scattering Experiment

Apparatus:

Radium a source of alpha particles.
Thin gold foil.
A lead box for emitted radiations.
Fluorescent or luminescent screen made up of ZnS.

A beam of high-speed, positively charged alpha particles (α particles) that were produced by the radioactive decay of radium (a radioactive element).

Experiment:

Rutherford fired α particles at a piece of thin gold foil and detected where those particles went.

Most of the α-particles (positive particles) passed straight through the foil and produced illumination on screen.
Some α-particles show deviation (slightly deflected from their path).
Very few α-particles (1/8000) rebound after striking.

Conclusion:

A beam of high-speed positively charged alpha particles (α particles) that were produced by the radioactive decay of radium (a radioactive element).
A small, relatively heavy, positively charged body, the nucleus, must be at the centre of each atom.

Main postulates:

Atom has a nucleus that contains practically the overall mass of the atom, leaving the rest of the atom almost empty.
The entire positive charge of the atom is located on the nucleus, while electrons were distributed in vacant (empty) space around it.
The electrons were moving in orbits or closed circular paths around the planets around the sun.

Defects of the Rutherford Atomic Model:

Rutherford’s Atomic Model suggested that electrons were circling around the nucleus. According to the laws of physics, if an electron loses energy, it should slow down and eventually fall into the nucleus. But, if that happened, the atom would become unstable, which is not the case. This was a major flaw in Rutherford’s Atomic Model.