Various Models of the Atom

Topic Content:

1. Thompson’s Atomic Model:

Thompson proposed that an atom consists of homologous sphere of positive charges which are embedded in negatively charged electrons

2. Rutherford Model of Atom:

Lord Ernest Rutherford , in 1911, used positively charged particles called Alpha particles to bombard a thin-gold foil. He found that most of the alpha particles passed through the foil, while a few of them were deflected back.

Rutherford explained his findings as follows:

a. Since most of the alpha particles passed through without being deflected, the atoms in the goldfield must contain a large space in which negative particles move.

b. Since very few of the alpha particles were deflected, the deflection might have been caused by a small region of the atom which consists of positive particles. The positive particles might have collided with the alpha particles, leading to the deflection.

c. Among the particles deflected, a few were deflected at large angles. This shows that the positive particles in the atom