Show diagrammatically the electron distributions in a sodium atom and a sodium ion and also give their atomic number.

(N/A) Since the atomic number of a sodium atom is $11$,it has $11$ electrons.
$A$ positively charged sodium ion $(Na^+)$ is formed by the removal of one electron from a sodium atom.
So,a sodium ion has $11 - 1 = 10$ electrons in it.
Thus,the electronic distribution of a sodium ion will be $2, 8$.
The atomic number of an element is equal to the number of protons in its atom.
Since a sodium atom and a sodium ion contain the same number of protons,the atomic number of both is $11$.