Answer:
1.helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
2.oxygen
Group 6A (or VIA) of the periodic table are the chalcogens: the nonmetals oxygen (O), sulfur (S), and selenium (Se), the metalloid tellurium (Te), and the metal polonium (Po).
