Answer
(a) sodium (Na) and iron (Fe)
(b) oxygen (O) and argon (Ar)
(c) silicon (Si) and antimony (Sb)
(d) nitrogen (N$_{2}$) and chlorine (Cl$_{2}$)
Work Step by Step
(a) Metals lie toward the left of the periodic table. Two examples of metals are sodium (Na) and iron (Fe).
(b) The nonmetals lie toward the right of the periodic table. Two example of nonmetals are oxygen (O) and argon (Ar).
(c) Metalloids lie along the dividing line between metals and nonmetals on the periodic table. These elements have characteristics of both metals and nonmetals. Two examples of metalloids are silicon (Si) and antimony (Sb).
(d) Two atoms of the same element that bond chemically together form a diatomic molecule. Some elements tend to exist in nature commonly as diatomic molecules. Two examples of diatomic molecules are nitrogen (N$_{2}$) and chlorine (Cl$_{2}$).
