Identify each of the following elements as a metal, nonmetal, or metalloid: (a) boron, (b) barium, (c) argon, (d) caesium, (e) yttrium, (f) astatine.

Before you can identify which category each element belongs to, you need to look up each element in the periodic table. The periodic table is organized in such a way that you can tell the type of an element by examining its position on the table.

After looking up each element in the periodic table, we can now identify them as metals, nonmetals, or metalloids based on the properties and their location on the periodic table. (a) Boron: Boron is a metalloid. It is found in Group 13 and Period 2 of the periodic table. Metalloids have a mix of metallic and nonmetallic properties. (b) Barium: Barium is a metal. It is located in Group 2 and Period 6 of the periodic table. Metals typically have a shiny appearance, are good conductors of heat and electricity, and are malleable. (c) Argon: Argon is a nonmetal. It is in Group 18 and Period 3 of the periodic table. Nonmetals are poor conductors of heat and electricity, and they do not have metallic luster. (d) Caesium: Caesium is a metal. It is located in Group 1 and Period 6 of the periodic table. Metals, as previously mentioned, have metallic luster, are good conductors of heat and electricity, and are malleable. (e) Yttrium: Yttrium is a metal. It is found in Group 3 and Period 5 of the periodic table. Yttrium has the properties typical of metals, such as metallic luster, good heat and electricity conductivity, and malleability. (f) Astatine: Astatine is a nonmetal. It is located in Group 17 and Period 6 of the periodic table. Nonmetals exhibit poor conductivity and lack the metallic luster present in metals. So, in summary, the classification of each element is as follows: - Boron: Metalloid - Barium: Metal - Argon: Nonmetal - Caesium: Metal - Yttrium: Metal - Astatine: Nonmetal