Rutherford's alpha $(\alpha)$ particles scattering experiment resulted in the discovery of:

Enlist the conclusions drawn by Rutherford from his $\alpha -$ ray scattering experiment.

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.

Why do Helium,Neon and Argon have a zero valency?

An element $X$ has a mass number $4$ and atomic number $2$. What is the valency of this element?

Fill in the blanks in the following statements:
$(a)$ Rutherford's $\alpha$-particle scattering experiment led to the discovery of the ............
$(b)$ Isotopes have same ............ but different .............
$(c)$ Neon and chlorine have atomic numbers $10$ and $17$ respectively. Their valencies will be ............ and ............. respectively.
$(d)$ The electronic configuration of silicon is .......... and that of sulphur is ...........