What is halogenation with explanation

Draw metallic bonding if two copper

Use this information to determine the number of calends electrons in the atoms. which of the following correctly compares the stability of the two atoms? a) both are unreactive b) both are highly reactive c) a is unreactive and d is reactive d) a is reactive and d is unreactive

Can someone me with 3 and 4 plz. this is for masteries test.