Answer:
Metallic bonding occurs when you have a metal in the solid or liquid state. The s and p valence electrons of metals are loosely held. They leave their “own” metal atoms. This forms a "sea" of electrons that surrounds the metal cations.
Explanation:
The largest atomic radius has Ba,because they are all metals of 2nd group,but as you know when you go down upright in the periodic table the metallic features getting stronger but also orbital layers increasing,and you can say more layers larger atomic radius.Hope I helped,sorry for English
-NH2 is the most favorable for the reaction