According to the Bohr-Bury scheme,the maximum number of electrons that can be accommodated in a given shell is given by the formula:

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 ...........

Identify the $Mg^{2+}$ ion from the figures,where $n$ and $p$ represent the number of neutrons and protons,respectively.

The ion of an element has $3$ positive charges. The mass number of the atom is $27$ and the number of neutrons is $14$. What is the number of electrons in the ion?

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

An atom with $3$ protons and $4$ neutrons will have a valency of: