Rutherford atomic model and its limitations - Practice Questions & MCQ

Rutherford's -scattering experiment

A stream of high energy α–particles from a radioactive source was directed at a thin foil (thickness ∼ 100 nm) of gold metal. The thin gold foil had a circular fluorescent zinc sulphide screen around it. Whenever α–particles struck the screen, a tiny flash of light was produced at that point

Observations of the Rutherford's experiment:

1. Most of the α–particles passed through the gold foil undeflected indicating that most of the atom is empty space.
2. A small fraction of the α–particles was deflected by small angles indicating that the postive charge is concentrated in a very small volume.
3. Very few α–particles (∼1 in 20,000) bounced back, that is, were deflected by nearly 180° thus confirming the size of nucleus to be very small.

Rutherford atomic models 

1. Most of the part of the atom is empty and atom is spherical in shape.

2. Each atom consists of a small, heavy, positively charged portion located at the centre, known as nucleus.

3. All positive charge of atom (i.e protons) are present in nucleus and electrons move around the nucleus in circular orbits.

4. Electrons and the nucleus are held together by electrostatic forces of attraction.

Limitations

1. According to Maxwell's theory, a moving charged particle under acceleration radiates energy and thus the electron must spiral into the nucleus, but that does not occur. The stability of the atom was not explained by the Rutherford's model.

2. Rutherford's model does not provide any information about the position of the electron or its energy.