The electronic configuration of sodium is

For sodium, ‘Na’ atomic number  $Z=11$

Electronic configuration of Na is  $1{\text{s}}^{2}2{\text{s}}^{2}2{\text{p}}^{6}3{\text{s}}^1\text{\hspace{0.17em}\hspace{0.17em}or \hspace{0.17em}}\left[\text{Ne}\right]3{\text{s}}^1$