Ernest Rutherford Atomic Model
Atomic model of Ernest Rutherford is also known as nuclear atom or planetary model of the atom. This description of atomic structure was proposed in 1911 by renowned physicist Ernest Rutherford.
His atomic theory stated that atom is a tiny and dense particle. A positively charged core is called nucleus, in which all the mass is concentrated. Around the nucleus, electrons circulated at some distance.
Rutherford’s gold foil experiment: –
- In this experiment, Rutherford bombarded alpha particles on a gold foil.
- A source which is going through alpha decay is placed in a lead box. The lead box had a small hole in it.
- Alpha particles that hit the inside of the box are stopped by the box.
- Particles which pass through the opening can escape. These particles follow a straight line and hit the gold foil.
Observations of gold foil experiment: –
- Most of the alpha particles follow the straight line and hot the gold foil.
- Some particles get deflected.
- A few alpha particles bounced of the foil and back to the left.
- Atom is 99.99% empty space.
- The nucleus has a positive charge and nearly all the mass of atom is concentrated in nucleus.
- The atom is approximately 100,000 times bigger than the nucleus.
Facts you didn’t know: –
- By this experiment, Rutherford determined the true nature of an atom and the phenomenon of radioactivity.
- His theory claimed that the atom is not one solid substance.