مصادر الكيمياء موقع لتعليم الكيمياء بصورة مبسطة
Rutherford model of atom
Rutherford observed that atom has all the positive charge concentrated in a very small central region called the nucleus and that nucleus is surrounded by negatively charged particles called electrons revolving in orbits. He proved that the force of attraction between electrons and nucleus was counter balanced by the centrifugal force acting on the revolving electron. This provided stability to the atom.
Rutherford explained the large scattering of alpha particles due to the presence of heavily charged positive nucleus. He bombarded a thin gold foil with alpha particles a found that alpha particles passing close to nucleus got deflected through greater angles. This was due to very strong repulsion particles suffered because of high concentrated positive charge.
Drawbacks of Rutherford’s atomic model:
1 – It could not explain the distribution of electrons outside the nucleus.
2 – It could not explain the stability of atom as whole.
According to fundamental law of electric magnetic theory an accelerated charge must emit electromagnetic energy or radiation continuously. The electrons therefore moving round the nucleus will continuously lose energy and finally they will spiral towards nucleus and fall into it when all the rotational energy got spent on radiations.