What is the ratio of the mass of a proton to the mass of an electron?

Rutherford's scattering experiment is related to the size of the

Fill in the blanks given below:
$(i)$ The circular path around the nucleus in which electrons revolve at high speed is called ......... .
$(ii)$ Electrons and the nucleus are held together by ......... force.
$(iii)$ The number of $P^{+}$ in the nucleus and the sum of the number of $P^{+}$ and $n^{\circ}$ in the nucleus are represented by the symbols ...... and ......... respectively.
$(iv)$ The sum of the number of $P^{+}$ and $n^{\circ}$ in the nucleus is represented by the term ...... and the symbol .... respectively.

$(i)$ Calculate the number of electrons which will together weigh $1 \, g$.
$(ii)$ Calculate the mass and charge of one mole of electrons.

The volume of the atomic nucleus is $......$ of the volume of the atom.

The nucleus and an atom can be assumed to be spherical. The radius of the nucleus of mass number $A$ is given by $R_n = 1.25 \times 10^{-13} \times A^{1/3} \, \text{cm}$. The atomic radius is $1 \, \mathring{A}$. If the mass number is $64$,the fraction of the atomic volume that is occupied by the nucleus is: