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

Name the three sub-atomic particles of an atom.

Isotopes of an element have

If the number of electrons in an atom is $8$ and the number of protons is also $8$,then $(i)$ what is the atomic number of the atom? and $(ii)$ what is the charge on the atom?

Describe Bohr's model of the atom.

Summarize the rules for writing the distribution of electrons in various shells for the first eighteen elements.