Final answer:
Sulfur is the nonmetal among the elements sodium, mercury, and manganese. This is because metals, like sodium, mercury, and manganese, form cations and ionic compounds, whereas nonmetals, like sulfur, form anions or molecular compounds.
Step-by-step explanation:
In chemistry, elements can be classified as metals, nonmetals, or metalloids. Looking at the elements Na (sodium), Hg (mercury), S (sulfur), and Mn (manganese), it can be determined that out of these four, S (sulfur) is a nonmetal. Sodium, mercury, and manganese are all metals or metal trace elements, while sulfur is a nonmetal.
Metals like sodium and mercury are typically known to form cations and ionic compounds with nonmetals in general. However, nonmetals like sulfur tend to form anions or molecular compounds. A combination of a nonmetal and a metal usually produces a salt, which is an ionic compound consisting of cations and anions.
Learn more about Nonmetals and Metals