Step-by-step explanation:
a) Barium
b) The metalloid in third period is Silicon
c) Group 4A (or IVA) of the periodic table includes the nonmetal carbon (C)
d) At this temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine and astatine are solids.
e) osmium
f) chlorine (Cl, element 17) are a gas at room temperature, and is found as diatomic molecule (Cl2).