Step-by-step explanation:
Sodium has atomic number of 11 with electronic configuration of :
![[Na]=1s^22s^22p63s^1](https://img.qammunity.org/2017/formulas/chemistry/high-school/qaw4l44l7iioozam44wmhsrqo8bu6rtbvq.png)
Sodium loose it single electron to attain stability of noble gas configuration. While this process electron gets removed from the outer shell of the sodium atom and it gains positive charge of +1.
![[Na^+]=1s^22s^22p63s^0](https://img.qammunity.org/2017/formulas/chemistry/high-school/m13qp4mc4uoymnq38ziqolte9kpnh8mtiy.png)
(Ionization)