The ratio of the radii of a hydrogen atom and its nucleus is $\sim 10^5$. Assuming the atom and the nucleus to be spherical,
$(i)$ What will be the ratio of their sizes (volumes)?
$(ii)$ If the atom is represented by the planet Earth $(R_e = 6.4 \times 10^6 \, m)$,estimate the size of the nucleus.

Atomic models have been improved over the years. Arrange the following atomic models in their chronological order:
$(i)$ Rutherford's atomic model
$(ii)$ Thomson's atomic model
$(iii)$ Bohr's atomic model

With the help of a labelled diagram,describe in brief the Rutherford's alpha particle scattering experiment. Write any three important conclusions drawn from the experiment.

During class,Ravi's teacher was teaching about Thomson's model of an atom,stating that an atom is electrically neutral,i.e.,it contains equal positive and negative charges,and that an atom consists of a sphere of positive charge in which electrons are embedded like plums in a pudding. Ravi wondered how his teacher related Thomson's model of an atom to a plum pudding,and he imagined that just as dry fruits are embedded in a Christmas pudding,electrons are embedded in a sphere of positive charge.
$(a)$ According to you,what kind of qualities does Ravi possess?
$(b)$ What are the limitations of Thomson's model?

The presence of electrons outside the nucleus and the nucleus at the centre of the atom was suggested by:

What do you think would be the observation if the $\alpha$-particle scattering experiment is carried out using a foil of a metal other than gold?