Answer: [tex]Br^-[/tex] , It is reduced.
Explanation:
Electronic configuration of sodium:
[tex][Na]=1s^22s^22p^63s^1[/tex]
Sodium atom will loose one electron to gain noble gas configuration and form sodium cation with +1 charge.
[tex][Na^+]=1s^22s^22p^63s^0[/tex]
Electronic configuration of bromine:
[tex][Br]:35:[Ar]3d^{10}4s^24p^5[/tex]
Bromine atom will gain one electron to gain noble gas configuration and form bromide ion with -1 charge.
[tex][Br^-]:36:[Ar]3d^{10}4s^24p^6[/tex]
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance decreases.
[tex]Br+e^-\rightarrow Br^-[/tex]
