Question

Observe the given figure and answer the questions that follows:

a) Name this experiment and List any one observation of this experiment:

(b) Mention 2 drawbacks of this model of an atom?​

Answer 1

Answer:

a)The Gold Foil experiment. Most of the fast moving α-particles passed straight through the gold foil.

b) i) The revolution of the electron in a circular orbit is not expected to be stable.

  ii)This model of the atom also failed to explain the existence of definite lines in the hydrogen spectrum.

Explanation:

a) This experiment was carried out by E. Rutherford. The name of the experiment is 'Gold Foil Experiment' because in this experiment, fast moving alpha (α)-particles were made to fall on a thin gold foil. This experiment gave unexpected results. The following observations were made :-

  i) Most of the fast moving α-particles passed straight through the gold foil.

 ii) Some of the α- particles were deflected by the foil by small angles.

iii) Surprisingly one out of every 12000 particles appeared to rebound.

b) The revolution of the electron in a circular orbit is not expected to be stable. Any particle in a circular orbit would undergo acceleration. During acceleration, charged particles would radiate energy. Thus, the revolving electrons would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable and hence matter would not exist in the form of the we know. We know that atoms are quite stable.