The electron configuration of sodium in excited state is [tex]1s^{2}2s^{2}2p^{6}3p^{1}[/tex]
Atomic number of sodium is [tex]11[/tex] i.e. it contains [tex]11[/tex] electrons.
The electron configuration of sodium in ground state is [tex]1s^{2}2s^{2}2p^{6}1s^{1}[/tex]
When sodium is in excited state the valance electron of [tex]3s[/tex] subshell jumps to [tex]3p[/tex] subshell on gaining energy.
The condition of sodium is very unstable and thus the outermost electron in [tex]3p[/tex] subshell will release energy and return back to its original orbital (that is [tex]3s[/tex]).
This will release equal energy which it absorbed to jump to [tex]3p[/tex] subshell producing yellow light.
To know more about electron configuration
https://brainly.com/question/13497372
#SPJ4