$(a)$ Which popular experiment is shown in the figure?
$(b)$ List three observations of this experiment.
$(c)$ State conclusions drawn from each observation of this experiment.
$(d)$ State the model of atom suggested on the basis of the above experiment.

(N/A) This figure shows the scattering of $\alpha$-particles by a gold foil (Rutherford's $\alpha$-particle scattering experiment).
$(b)$ Observations:
$(i)$ Most of the $\alpha$-particles passed straight through the gold foil.
$(ii)$ Some of the $\alpha$-particles were deflected by the foil by small angles.
$(iii)$ One out of every $12000$ particles appeared to rebound.
$(c)$ Conclusions:
$(i)$ Most of the space inside the atom is empty.
$(ii)$ The positive charge of the atom occupies very little space.
$(iii)$ All the positive charge and mass of the atom is concentrated in a very small volume within the atom.
$(d)$ Rutherford's Model of the atom:
$(i)$ There is a positively charged center in an atom called the nucleus,which contains the whole mass of the atom.
$(ii)$ The electrons revolve around the nucleus in well-defined orbits.
$(iii)$ The size of the nucleus is very small as compared to the size of the atom.