A barium atom attains a stable electron configuration when it bonds with two chlorine atoms.
-Barium is an alkaline earth metal, in group two of the periodic table. Like other alkaline earth metal it has a valency of two which means it reacts by loosing two electrons.
-Chlorine on the other hand is a halogen (group seven element) it reacts by gaining an electron, thus two chlorine atoms will require two electrons. Therefore, Barium would attain a stable configuration by loosing two electrons to two chlorine atoms.
Pedigree charts are used to see traits that are present in families or individuals. For example, it can be used see if certain diseases are running through someone's family and if that individual will inherit the disease.