Examine Figure 2.3, The periodic table. (f) Classify the following three elements as metals, nonmet-als, or semimetals: Mo, Br, Si.

The periodic table organizes elements based on their atomic number and properties. Elements are classified into three main categories: metals, nonmetals, and semimetals (or metalloids). Metals, typically found on the left side and center of the table, are good conductors of heat and electricity. Nonmetals, located on the right side, have varied properties and are generally poor conductors. Semimetals exhibit characteristics of both metals and nonmetals.

Metals are characterized by their luster, malleability, ductility, and good electrical and thermal conductivity. They tend to lose electrons during chemical reactions, forming positive ions. Common examples include elements like iron (Fe) and copper (Cu). In the context of the question, molybdenum (Mo) is classified as a metal due to these properties.

Nonmetals are generally poor conductors of heat and electricity and can gain or share electrons in chemical reactions, forming negative ions or covalent bonds. Bromine (Br) is a nonmetal, known for its reactivity and existence as a liquid at room temperature. Semimetals, like silicon (Si), have intermediate properties; they can conduct electricity better than nonmetals but not as well as metals, making them essential in electronics.