On the basis of Rutherford's model of an atom,which subatomic particle is present in the nucleus of an atom?

What are canal rays?

If $K$ and $L$ shells of an atom are full,then what would be the total number of electrons in the atom?

Helium atom has an atomic mass of $4 \, u$ and two protons in its nucleus. How many neutrons does it have?

Explain with examples $(i)$ Atomic number,$(ii)$ Mass number. Give any two uses of isotopes.

If bromine atom is available in the form of,say,two isotopes $_{35}^{79}Br$ $(49.7 \%)$ and $_{35}^{81}Br$ $(50.3 \%),$ calculate the average atomic mass of bromine atom. (in $,u$)