Which selection contains elements that are not all in the same group?

sodium, potassium, rubidium

fluorine, chlorine, bromine

argon, krypton, xenon

iron, copper, calcium

Iron, copper , calcium

Explanation:

Iron , copper and calcium are present in three different groups.

Iron is present in group eight.

Copper is present in group eleven.

Calcium is present in group two.

Sodium , potassium and rubidium are present in same group i.e. group one. These are alkali metals.

Fluorine, chlorine and bromine are present in group seventeen. These are halogens.

Argon, Krypton and xenon are present in same group i.e, group eighteen. All are these noble gases.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a