Little is known about the properties of astatine, At, because of its rarity and high radioactivity. Nevertheless, it is possible for us to make many predictions about its properties.
(a) Do you expect the element to be a gas, liquid, or solid at room temperature? Explain.
(b) Would you expect At to be a metal, nonmetal, or metalloid? Explain.
(c) What is the chemical formula of the compound it forms with Na?