De quin element és el símbol

Na ____________________ Pb ____________________ Sn ____________________ H ____________________ K ____________________ Al ____________________ Li ____________________ C ____________________ Ra ____________________ Bi ____________________ As ____________________ Sr ____________________ Ba ____________________ Mg ____________________ Rb ____________________ Cs ____________________ B ____________________ P ____________________ Ge ____________________ Sb ____________________ Ga ____________________ Ca ____________________ Be ____________________