Question

What are the Defects of Rutherford's model of atom?

Answer 1

Postulates of Rutherford's model of an atom:

• Rutherford designed a gold-foil experiment.
• In his experiment, the $\mathrm{\alpha }-$particles were made to come down on a thin gold foil.
• Many of the $\mathrm{\alpha }-$particles passed linearly through the gold foil.
• Some of the particles deviated at small angles.
• One out of every $12000$ particles appeared to bounce.

Conclusion of Rutherford's model of an atom:

• The space inside an atom is empty as most of the $\mathrm{\alpha }-$particles passed without deflection through the gold foil.
• The positive charge occupies a minimum space which indicates that very few particles were diverted from their path.
• A very small proportion of $\mathrm{\alpha }-$particles were diverted by ${180}^{\mathrm{o}}$, indicating that all the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.

Defects of Rutherford's model of an atom:

• The movement of electrons was not specified by him and was expected to be unstable.
• Any particle in a circular orbit undergoes acceleration. During acceleration, charged particles would radiate energy. Thus, the revolving electron would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable.