what is Rutherford's scattering experiment? Write the main features of the Rutherford's model of an atom.
Answers
Rutherford conducted alpha scattering experiment and put forward a model of atom known as Rutherford’s nuclear model. The salient features of this model are as follows:
(i) The atom contains a central part called nucleus which is surrounded by electrons.
(ii) The nucleus of an atom is positively charged.
(iii) The size of the nucleus is very small as compared to the atomic size.
(iv) The mass of an atom is mainly concentrated within its nucleus.
(v) Atom as a whole is electrically neutral, i.e., number of protons inside the nucleus of an atom and the number of electrons surrounding it are equal.
(vi) Nucleus is dense and hard and most of the atom is hollow.
(vii) To explain that the electrons do not fall into the nucleus because of attraction, Rutherford said that electrons were not stationary but were revolving around the nucleus in certain circular orbits. The force of attraction is balanced by the centrifugal force which comes into play due to revolution.
Rutherford’s nuclear model is similar to our solar system where the nucleus is like the sun and the electrons are like the planets.
On the basis of his experiment, Rutherford put forward the model of an atom, which had the following features:
- There is a positively charged centre in an atom called the nucleus.
- Nearly all the mass of an atom resides in the nucleus.
- The electrons revolve around the nucleus in well-defined orbits.