Question

What are the main postulates of Rutherford's Atomic Model and what are the causes of failure of this model?

Answer 1

Postulates of Rutherford's model of an atom:

• In his experiment, the $\mathrm{\alpha }-$particles were made to strike 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 $12000$ particle appeared to bounce.

Conclusions 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 ${180}^{\mathrm{o}}$.

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 and radiate energy due to which the revolving particle identified by Rutherford was unstable as they tend to fall inside the nucleus.